81919056 has 40 divisors (see below), whose sum is σ = 224074944. Its totient is φ = 25699840.

The previous prime is 81919049. The next prime is 81919063. The reversal of 81919056 is 65091918.

It is an interprime number because it is at equal distance from previous prime (81919049) and next prime (81919063).

It is a super-2 number, since 2×81919056² = 13421463471862272, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49380 + ... + 51011.

Almost surely, 2^81919056 is an apocalyptic number.

It is an amenable number.

81919056 is an abundant number, since it is smaller than the sum of its proper divisors (142155888).

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

81919056 is a wasteful number, since it uses less digits than its factorization.

81919056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100419 (or 100413 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 39.

The square root of 81919056 is about 9050.9146499125. The cubic root of 81919056 is about 434.3051504130.

The spelling of 81919056 in words is "eighty-one million, nine hundred nineteen thousand, fifty-six".