813956640 has 144 divisors (see below), whose sum is σ = 2982655872. Its totient is φ = 186041856.

The previous prime is 813956639. The next prime is 813956653. The reversal of 813956640 is 46659318.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 813956592 and 813956601.

It is an unprimeable 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 23 ways as a sum of consecutive naturals, for example, 6217 + ... + 40823.

It is an arithmetic number, because the mean of its divisors is an integer number (20712888).

Almost surely, 2^813956640 is an apocalyptic number.

813956640 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 813956640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1491327936).

813956640 is an abundant number, since it is smaller than the sum of its proper divisors (2168699232).

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

813956640 is a wasteful number, since it uses less digits than its factorization.

813956640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34639 (or 34624 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 42.

The square root of 813956640 is about 28529.9253416478. The cubic root of 813956640 is about 933.6850896350.

The spelling of 813956640 in words is "eight hundred thirteen million, nine hundred fifty-six thousand, six hundred forty".