81772506647 has 8 divisors (see below), whose sum is σ = 88870615680. Its totient is φ = 74789814240.

The previous prime is 81772506631. The next prime is 81772506727. The reversal of 81772506647 is 74660527718.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81772506647 - 2⁴ = 81772506631 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81772506617) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28852679 + ... + 28855512.

It is an arithmetic number, because the mean of its divisors is an integer number (11108826960).

Almost surely, 2^81772506647 is an apocalyptic number.

81772506647 is a deficient number, since it is larger than the sum of its proper divisors (7098109033).

81772506647 is a wasteful number, since it uses less digits than its factorization.

81772506647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57708313.

The product of its (nonzero) digits is 3951360, while the sum is 53.

The spelling of 81772506647 in words is "eighty-one billion, seven hundred seventy-two million, five hundred six thousand, six hundred forty-seven".