81619568 has 10 divisors (see below), whose sum is σ = 158137944. Its totient is φ = 40809776.

The previous prime is 81619553. The next prime is 81619579. The reversal of 81619568 is 86591618.

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, 2550596 + ... + 2550627.

Almost surely, 2^81619568 is an apocalyptic number.

It is an amenable number.

81619568 is a deficient number, since it is larger than the sum of its proper divisors (76518376).

81619568 is a wasteful number, since it uses less digits than its factorization.

81619568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5101231 (or 5101225 counting only the distinct ones).

The product of its digits is 103680, while the sum is 44.

The square root of 81619568 is about 9034.3548745884. The cubic root of 81619568 is about 433.7752451761.

The spelling of 81619568 in words is "eighty-one million, six hundred nineteen thousand, five hundred sixty-eight".