81851500477475 has 48 divisors (see below), whose sum is σ = 106187308904640. Its totient is φ = 62469472665600.

The previous prime is 81851500477421. The next prime is 81851500477511. The reversal of 81851500477475 is 57477400515818.

It is not a de Polignac number, because 81851500477475 - 2²² = 81851496283171 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3123017171 + ... + 3123043379.

It is an arithmetic number, because the mean of its divisors is an integer number (2212235602180).

Almost surely, 2^{81851500477475} is an apocalyptic number.

81851500477475 is a deficient number, since it is larger than the sum of its proper divisors (24335808427165).

81851500477475 is a wasteful number, since it uses less digits than its factorization.

81851500477475 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40320 (or 40315 counting only the distinct ones).

The product of its (nonzero) digits is 43904000, while the sum is 62.

The spelling of 81851500477475 in words is "eighty-one trillion, eight hundred fifty-one billion, five hundred million, four hundred seventy-seven thousand, four hundred seventy-five".