813066640 has 80 divisors (see below), whose sum is σ = 1944237168. Its totient is φ = 316080128.

The previous prime is 813066637. The next prime is 813066671. The reversal of 813066640 is 46660318.

813066640 = T₁ + T₂ + ... + T₁₆₉₅.

813066640 is a nontrivial binomial coefficient, being equal to C(1697, 3).

It can be written as a sum of positive squares in 8 ways, for example, as 132496 + 812934144 = 364^2 + 28512^2 .

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×813066640² = 1322154722161779200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 813066596 and 813066605.

It is an unprimeable number.

It is the 1695-th tetrahedral number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 478272 + ... + 479968.

Almost surely, 2^813066640 is an apocalyptic number.

813066640 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 813066640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (972118584).

813066640 is an abundant number, since it is smaller than the sum of its proper divisors (1131170528).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

813066640 is a wasteful number, since it uses less digits than its factorization.

813066640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1876 (or 1870 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 34.

The square root of 813066640 is about 28514.3234182402. The cubic root of 813066640 is about 933.3446608603.

The spelling of 813066640 in words is "eight hundred thirteen million, sixty-six thousand, six hundred forty".