81251164 has 6 divisors (see below), whose sum is σ = 142189544. Its totient is φ = 40625580.

The previous prime is 81251153. The next prime is 81251227. The reversal of 81251164 is 46115218.

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, 10156392 + ... + 10156399.

Almost surely, 2^81251164 is an apocalyptic number.

It is an amenable number.

81251164 is a deficient number, since it is larger than the sum of its proper divisors (60938380).

81251164 is a wasteful number, since it uses less digits than its factorization.

81251164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20312795 (or 20312793 counting only the distinct ones).

The product of its digits is 1920, while the sum is 28.

The square root of 81251164 is about 9013.9427555316. The cubic root of 81251164 is about 433.1216209730.

The spelling of 81251164 in words is "eighty-one million, two hundred fifty-one thousand, one hundred sixty-four".