813639965040 has 800 divisors, whose sum is σ = 3266825481216. Its totient is φ = 183847034880.

The previous prime is 813639965029. The next prime is 813639965041. The reversal of 813639965040 is 40569936318.

813639965040 is a `hidden beast` number, since 8 + 13 + 6 + 39 + 96 + 504 + 0 = 666.

813639965040 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (813639965041) by changing a digit.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 2875052739 + ... + 2875053021.

Almost surely, 2^813639965040 is an apocalyptic number.

813639965040 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 813639965040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1633412740608).

813639965040 is an abundant number, since it is smaller than the sum of its proper divisors (2453185516176).

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

813639965040 is a wasteful number, since it uses less digits than its factorization.

813639965040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 819 (or 804 counting only the distinct ones).

The product of its (nonzero) digits is 4199040, while the sum is 54.

It can be divided in two parts, 81363 and 9965040, that added together give a triangular number (10046403 = T₄₄₈₂).

The spelling of 813639965040 in words is "eight hundred thirteen billion, six hundred thirty-nine million, nine hundred sixty-five thousand, forty".