81569352672 has 96 divisors (see below), whose sum is σ = 251905399200. Its totient is φ = 25590380544.

The previous prime is 81569352607. The next prime is 81569352673. The reversal of 81569352672 is 27625396518.

81569352672 is a `hidden beast` number, since 8 + 1 + 569 + 3 + 5 + 2 + 6 + 72 = 666.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×81569352672² (a number of 23 digits) contains 22 as substring.

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 (81569352673) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2762047 + ... + 2791422.

It is an arithmetic number, because the mean of its divisors is an integer number (2624014575).

Almost surely, 2^81569352672 is an apocalyptic number.

It is an amenable number.

81569352672 is an abundant number, since it is smaller than the sum of its proper divisors (170336046528).

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

81569352672 is a wasteful number, since it uses less digits than its factorization.

81569352672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5553505 (or 5553491 counting only the distinct ones).

The product of its digits is 5443200, while the sum is 54.

The spelling of 81569352672 in words is "eighty-one billion, five hundred sixty-nine million, three hundred fifty-two thousand, six hundred seventy-two".