51620661 has 12 divisors (see below), whose sum is σ = 76578892. Its totient is φ = 33483456.

The previous prime is 51620659. The next prime is 51620669. The reversal of 51620661 is 16602615.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 23328900 + 28291761 = 4830^2 + 5319^2 .

It is not a de Polignac number, because 51620661 - 2¹ = 51620659 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 (51620669) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 77176 + ... + 77841.

Almost surely, 2^51620661 is an apocalyptic number.

It is an amenable number.

51620661 is a deficient number, since it is larger than the sum of its proper divisors (24958231).

51620661 is a wasteful number, since it uses less digits than its factorization.

51620661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155060 (or 155057 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 51620661 is about 7184.7519790178. The cubic root of 51620661 is about 372.3412797665.

The spelling of 51620661 in words is "fifty-one million, six hundred twenty thousand, six hundred sixty-one".