81620992 has 26 divisors (see below), whose sum is σ = 163230248. Its totient is φ = 40808448.

The previous prime is 81620977. The next prime is 81621019. The reversal of 81620992 is 29902618.

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, 5868 + ... + 14059.

Almost surely, 2^81620992 is an apocalyptic number.

It is an amenable number.

81620992 is a deficient number, since it is larger than the sum of its proper divisors (81609256).

81620992 is an equidigital number, since it uses as much as digits as its factorization.

81620992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19951 (or 19929 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 37.

The square root of 81620992 is about 9034.4336845206. The cubic root of 81620992 is about 433.7777678243. Note that the first 4 decimals are identical.

The spelling of 81620992 in words is "eighty-one million, six hundred twenty thousand, nine hundred ninety-two".