51891905 has 32 divisors (see below), whose sum is σ = 71705088. Its totient is φ = 35712000.

The previous prime is 51891899. The next prime is 51891911. The reversal of 51891905 is 50919815.

It is an interprime number because it is at equal distance from previous prime (51891899) and next prime (51891911).

It is not a de Polignac number, because 51891905 - 2¹² = 51887809 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 166700 + ... + 167010.

It is an arithmetic number, because the mean of its divisors is an integer number (2240784).

Almost surely, 2^51891905 is an apocalyptic number.

It is an amenable number.

51891905 is a deficient number, since it is larger than the sum of its proper divisors (19813183).

51891905 is a wasteful number, since it uses less digits than its factorization.

With its predecessor (51891904) it forms a Ruth-Aaron pair, since the sum of their prime factors is the same (497).

51891905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 497.

The product of its (nonzero) digits is 16200, while the sum is 38.

The square root of 51891905 is about 7203.6036120819. The cubic root of 51891905 is about 372.9923043452.

The spelling of 51891905 in words is "fifty-one million, eight hundred ninety-one thousand, nine hundred five".