51906621 has 16 divisors (see below), whose sum is σ = 74674880. Its totient is φ = 31881600.

The previous prime is 51906587. The next prime is 51906667. The reversal of 51906621 is 12660915.

It is not a de Polignac number, because 51906621 - 2¹⁰ = 51905597 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51906221) 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, 27921 + ... + 29721.

It is an arithmetic number, because the mean of its divisors is an integer number (4667180).

Almost surely, 2^51906621 is an apocalyptic number.

It is an amenable number.

51906621 is a deficient number, since it is larger than the sum of its proper divisors (22768259).

51906621 is a wasteful number, since it uses less digits than its factorization.

51906621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2556.

The product of its (nonzero) digits is 3240, while the sum is 30.

The square root of 51906621 is about 7204.6249728907. The cubic root of 51906621 is about 373.0275599145.

It can be divided in two parts, 5190 and 6621, that added together give a palindrome (11811).

The spelling of 51906621 in words is "fifty-one million, nine hundred six thousand, six hundred twenty-one".