56921621 has 2 divisors, whose sum is σ = 56921622. Its totient is φ = 56921620.

The previous prime is 56921617. The next prime is 56921687. The reversal of 56921621 is 12612965.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 46104100 + 10817521 = 6790^2 + 3289^2 .

It is a cyclic number.

It is not a de Polignac number, because 56921621 - 2² = 56921617 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (56921521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28460810 + 28460811.

It is an arithmetic number, because the mean of its divisors is an integer number (28460811).

Almost surely, 2^56921621 is an apocalyptic number.

It is an amenable number.

56921621 is a deficient number, since it is larger than the sum of its proper divisors (1).

56921621 is an equidigital number, since it uses as much as digits as its factorization.

56921621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6480, while the sum is 32.

The square root of 56921621 is about 7544.6418735418. The cubic root of 56921621 is about 384.6736335748.

The spelling of 56921621 in words is "fifty-six million, nine hundred twenty-one thousand, six hundred twenty-one".