81724257952 has 12 divisors (see below), whose sum is σ = 160894632906. Its totient is φ = 40862128960.

The previous prime is 81724257941. The next prime is 81724257983. The reversal of 81724257952 is 25975242718.

It can be written as a sum of positive squares in only one way, i.e., 81615347856 + 108910096 = 285684^2 + 10436^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 81724257952.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1276941499 + ... + 1276941562.

Almost surely, 2^81724257952 is an apocalyptic number.

It is an amenable number.

81724257952 is a deficient number, since it is larger than the sum of its proper divisors (79170374954).

81724257952 is a wasteful number, since it uses less digits than its factorization.

81724257952 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2553883071 (or 2553883063 counting only the distinct ones).

The product of its digits is 2822400, while the sum is 52.

The spelling of 81724257952 in words is "eighty-one billion, seven hundred twenty-four million, two hundred fifty-seven thousand, nine hundred fifty-two".