81025690868 has 6 divisors (see below), whose sum is σ = 141794959026. Its totient is φ = 40512845432.

The previous prime is 81025690859. The next prime is 81025690873. The reversal of 81025690868 is 86809652018.

It can be written as a sum of positive squares in only one way, i.e., 79997334244 + 1028356624 = 282838^2 + 32068^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10128211355 + ... + 10128211362.

It is an arithmetic number, because the mean of its divisors is an integer number (23632493171).

Almost surely, 2^81025690868 is an apocalyptic number.

It is an amenable number.

81025690868 is a deficient number, since it is larger than the sum of its proper divisors (60769268158).

81025690868 is a wasteful number, since it uses less digits than its factorization.

81025690868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20256422721 (or 20256422719 counting only the distinct ones).

The product of its (nonzero) digits is 1658880, while the sum is 53.

The spelling of 81025690868 in words is "eighty-one billion, twenty-five million, six hundred ninety thousand, eight hundred sixty-eight".