81723859875 has 384 divisors, whose sum is σ = 190914796800. Its totient is φ = 34255872000.

The previous prime is 81723859859. The next prime is 81723859897. The reversal of 81723859875 is 57895832718.

81723859875 is a `hidden beast` number, since 8 + 1 + 7 + 2 + 38 + 598 + 7 + 5 = 666.

It is not a de Polignac number, because 81723859875 - 2⁴ = 81723859859 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 115266021 + ... + 115266729.

It is an arithmetic number, because the mean of its divisors is an integer number (497173950).

Almost surely, 2^81723859875 is an apocalyptic number.

81723859875 is a gapful number since it is divisible by the number (85) formed by its first and last digit.

81723859875 is an abundant number, since it is smaller than the sum of its proper divisors (109190936925).

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

81723859875 is a wasteful number, since it uses less digits than its factorization.

81723859875 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 805 (or 782 counting only the distinct ones).

The product of its digits is 33868800, while the sum is 63.

The spelling of 81723859875 in words is "eighty-one billion, seven hundred twenty-three million, eight hundred fifty-nine thousand, eight hundred seventy-five".