81601996 has 24 divisors (see below), whose sum is σ = 164457216. Its totient is φ = 34703760.

The previous prime is 81601991. The next prime is 81602029. The reversal of 81601996 is 69910618.

It is not an unprimeable number, because it can be changed into a prime (81601991) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7456 + ... + 14791.

It is an arithmetic number, because the mean of its divisors is an integer number (6852384).

Almost surely, 2^81601996 is an apocalyptic number.

It is an amenable number.

81601996 is an abundant number, since it is smaller than the sum of its proper divisors (82855220).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81601996 is a wasteful number, since it uses less digits than its factorization.

81601996 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22389 (or 22387 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 40.

The square root of 81601996 is about 9033.3823122903. The cubic root of 81601996 is about 433.7441135661.

The spelling of 81601996 in words is "eighty-one million, six hundred one thousand, nine hundred ninety-six".