81194021325 has 36 divisors (see below), whose sum is σ = 150813729248. Its totient is φ = 43303474800.

The previous prime is 81194021309. The next prime is 81194021341. The reversal of 81194021325 is 52312049118.

81194021325 is a `hidden beast` number, since 8 + 119 + 402 + 132 + 5 = 666.

It is an interprime number because it is at equal distance from previous prime (81194021309) and next prime (81194021341).

It is not a de Polignac number, because 81194021325 - 2⁴ = 81194021309 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81194021325.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 6676561 + ... + 6688710.

Almost surely, 2^81194021325 is an apocalyptic number.

It is an amenable number.

81194021325 is a deficient number, since it is larger than the sum of its proper divisors (69619707923).

81194021325 is a wasteful number, since it uses less digits than its factorization.

81194021325 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13365296 (or 13365279 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The spelling of 81194021325 in words is "eighty-one billion, one hundred ninety-four million, twenty-one thousand, three hundred twenty-five".