81871615 has 16 divisors (see below), whose sum is σ = 113637888. Its totient is φ = 55462176.

The previous prime is 81871607. The next prime is 81871631. The reversal of 81871615 is 51617818.

It is not a de Polignac number, because 81871615 - 2³ = 81871607 is a prime.

It is a super-2 number, since 2×81871615² = 13405922685416450, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11187 + ... + 16996.

It is an arithmetic number, because the mean of its divisors is an integer number (7102368).

Almost surely, 2^81871615 is an apocalyptic number.

81871615 is a deficient number, since it is larger than the sum of its proper divisors (31766273).

81871615 is a wasteful number, since it uses less digits than its factorization.

81871615 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28278.

The product of its digits is 13440, while the sum is 37.

The square root of 81871615 is about 9048.2934855143. The cubic root of 81871615 is about 434.2212958932.

The spelling of 81871615 in words is "eighty-one million, eight hundred seventy-one thousand, six hundred fifteen".