51691541 has 4 divisors (see below), whose sum is σ = 56390784. Its totient is φ = 46992300.

The previous prime is 51691537. The next prime is 51691559. The reversal of 51691541 is 14519615.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 51691541 - 2² = 51691537 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 51691498 and 51691507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51691531) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2349605 + ... + 2349626.

It is an arithmetic number, because the mean of its divisors is an integer number (14097696).

Almost surely, 2^51691541 is an apocalyptic number.

It is an amenable number.

51691541 is a deficient number, since it is larger than the sum of its proper divisors (4699243).

51691541 is a wasteful number, since it uses less digits than its factorization.

51691541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4699242.

The product of its digits is 5400, while the sum is 32.

The square root of 51691541 is about 7189.6829554578. The cubic root of 51691541 is about 372.5116216364.

The spelling of 51691541 in words is "fifty-one million, six hundred ninety-one thousand, five hundred forty-one".