51105691 has 16 divisors (see below), whose sum is σ = 63093184. Its totient is φ = 40310784.

The previous prime is 51105667. The next prime is 51105707. The reversal of 51105691 is 19650115.

51105691 = T₂₅₃ + T₂₅₄ + ... + T₆₈₅.

It is a 11-Lehmer number, since φ(51105691) divides (51105691-1)¹¹.

It is a cyclic number.

It is not a de Polignac number, because 51105691 - 2¹⁹ = 50581403 is a prime.

It is a super-2 number, since 2×51105691² = 5223583305174962, which contains 22 as substring.

51105691 is a modest number, since divided by 5691 gives 511 as remainder.

It is not an unprimeable number, because it can be changed into a prime (51105641) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38755 + ... + 40051.

It is an arithmetic number, because the mean of its divisors is an integer number (3943324).

Almost surely, 2^51105691 is an apocalyptic number.

51105691 is a deficient number, since it is larger than the sum of its proper divisors (11987493).

51105691 is a wasteful number, since it uses less digits than its factorization.

51105691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1750.

The product of its (nonzero) digits is 1350, while the sum is 28.

The square root of 51105691 is about 7148.8244488167. The cubic root of 51105691 is about 371.0989751019.

It can be divided in two parts, 5110 and 5691, that added together give a palindrome (10801).

The spelling of 51105691 in words is "fifty-one million, one hundred five thousand, six hundred ninety-one".