81458525128 has 8 divisors (see below), whose sum is σ = 152734734630. Its totient is φ = 40729262560.

The previous prime is 81458525119. The next prime is 81458525147. The reversal of 81458525128 is 82152585418.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 80291756164 + 1166768964 = 283358^2 + 34158^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5091157813 + ... + 5091157828.

Almost surely, 2^81458525128 is an apocalyptic number.

It is an amenable number.

81458525128 is a deficient number, since it is larger than the sum of its proper divisors (71276209502).

81458525128 is a wasteful number, since it uses less digits than its factorization.

81458525128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10182315647 (or 10182315643 counting only the distinct ones).

The product of its digits is 1024000, while the sum is 49.

The spelling of 81458525128 in words is "eighty-one billion, four hundred fifty-eight million, five hundred twenty-five thousand, one hundred twenty-eight".