55840621 has 2 divisors, whose sum is σ = 55840622. Its totient is φ = 55840620.

The previous prime is 55840613. The next prime is 55840627. The reversal of 55840621 is 12604855.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 47803396 + 8037225 = 6914^2 + 2835^2 .

It is a cyclic number.

It is not a de Polignac number, because 55840621 - 2³ = 55840613 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55840627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27920310 + 27920311.

It is an arithmetic number, because the mean of its divisors is an integer number (27920311).

Almost surely, 2^55840621 is an apocalyptic number.

It is an amenable number.

55840621 is a deficient number, since it is larger than the sum of its proper divisors (1).

55840621 is an equidigital number, since it uses as much as digits as its factorization.

55840621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9600, while the sum is 31.

The square root of 55840621 is about 7472.6582285021. The cubic root of 55840621 is about 382.2229380389. Note that the first 3 decimals are identical.

The spelling of 55840621 in words is "fifty-five million, eight hundred forty thousand, six hundred twenty-one".