81724251345 has 32 divisors (see below), whose sum is σ = 142660583424. Its totient is φ = 39619819200.

The previous prime is 81724251341. The next prime is 81724251359. The reversal of 81724251345 is 54315242718.

It is not a de Polignac number, because 81724251345 - 2² = 81724251341 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81724251297 and 81724251306.

It is not an unprimeable number, because it can be changed into a prime (81724251341) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2156410 + ... + 2193980.

It is an arithmetic number, because the mean of its divisors is an integer number (4458143232).

Almost surely, 2^81724251345 is an apocalyptic number.

It is an amenable number.

81724251345 is a deficient number, since it is larger than the sum of its proper divisors (60936332079).

81724251345 is a wasteful number, since it uses less digits than its factorization.

81724251345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50773.

The product of its digits is 268800, while the sum is 42.

The spelling of 81724251345 in words is "eighty-one billion, seven hundred twenty-four million, two hundred fifty-one thousand, three hundred forty-five".