813187871640 has 320 divisors, whose sum is σ = 2788312887360. Its totient is φ = 212522434560.

The previous prime is 813187871609. The next prime is 813187871641. The reversal of 813187871640 is 46178781318.

It is a super-2 number, since 2×813187871640² (a number of 25 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

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 (813187871641) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 32358280 + ... + 32383400.

It is an arithmetic number, because the mean of its divisors is an integer number (8713477773).

Almost surely, 2^813187871640 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 813187871640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1394156443680).

813187871640 is an abundant number, since it is smaller than the sum of its proper divisors (1975125015720).

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

813187871640 is a wasteful number, since it uses less digits than its factorization.

813187871640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25344 (or 25331 counting only the distinct ones).

The product of its (nonzero) digits is 1806336, while the sum is 54.

The spelling of 813187871640 in words is "eight hundred thirteen billion, one hundred eighty-seven million, eight hundred seventy-one thousand, six hundred forty".