813536640 has 192 divisors, whose sum is σ = 3210723360. Its totient is φ = 185942016.

The previous prime is 813536617. The next prime is 813536653. The reversal of 813536640 is 46635318.

813536640 is a `hidden beast` number, since 8 + 1 + 3 + 5 + 3 + 6 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 813536595 and 813536604.

It is a congruent number.

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, 30232 + ... + 50408.

Almost surely, 2^813536640 is an apocalyptic number.

813536640 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 813536640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1605361680).

813536640 is an abundant number, since it is smaller than the sum of its proper divisors (2397186720).

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

813536640 is a wasteful number, since it uses less digits than its factorization.

813536640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20209 (or 20194 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 813536640 is about 28522.5636996396. The cubic root of 813536640 is about 933.5244687916.

The spelling of 813536640 in words is "eight hundred thirteen million, five hundred thirty-six thousand, six hundred forty".