51905661 has 4 divisors (see below), whose sum is σ = 69207552. Its totient is φ = 34603772.

The previous prime is 51905653. The next prime is 51905669. The reversal of 51905661 is 16650915.

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 an interprime number because it is at equal distance from previous prime (51905653) and next prime (51905669).

It is a cyclic number.

It is not a de Polignac number, because 51905661 - 2³ = 51905653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51905669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8650941 + ... + 8650946.

It is an arithmetic number, because the mean of its divisors is an integer number (17301888).

Almost surely, 2^51905661 is an apocalyptic number.

It is an amenable number.

51905661 is a deficient number, since it is larger than the sum of its proper divisors (17301891).

51905661 is a wasteful number, since it uses less digits than its factorization.

51905661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17301890.

The product of its (nonzero) digits is 8100, while the sum is 33.

The square root of 51905661 is about 7204.5583487123. The cubic root of 51905661 is about 373.0252602165.

The spelling of 51905661 in words is "fifty-one million, nine hundred five thousand, six hundred sixty-one".