81949724152 has 32 divisors (see below), whose sum is σ = 154554998400. Its totient is φ = 40735180384.

The previous prime is 81949724123. The next prime is 81949724173. The reversal of 81949724152 is 25142794918.

It is a self number, because there is not a number n which added to its sum of digits gives 81949724152.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10769133 + ... + 10776739.

It is an arithmetic number, because the mean of its divisors is an integer number (4829843700).

Almost surely, 2^81949724152 is an apocalyptic number.

It is an amenable number.

81949724152 is a deficient number, since it is larger than the sum of its proper divisors (72605274248).

81949724152 is a wasteful number, since it uses less digits than its factorization.

81949724152 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15315 (or 15311 counting only the distinct ones).

The product of its digits is 1451520, while the sum is 52.

The spelling of 81949724152 in words is "eighty-one billion, nine hundred forty-nine million, seven hundred twenty-four thousand, one hundred fifty-two".