55031621 has 2 divisors, whose sum is σ = 55031622. Its totient is φ = 55031620.

The previous prime is 55031611. The next prime is 55031623. The reversal of 55031621 is 12613055.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 40780996 + 14250625 = 6386^2 + 3775^2 .

It is a cyclic number.

It is not a de Polignac number, because 55031621 - 2¹⁰ = 55030597 is a prime.

Together with 55031623, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55031623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27515810 + 27515811.

It is an arithmetic number, because the mean of its divisors is an integer number (27515811).

Almost surely, 2^55031621 is an apocalyptic number.

It is an amenable number.

55031621 is a deficient number, since it is larger than the sum of its proper divisors (1).

55031621 is an equidigital number, since it uses as much as digits as its factorization.

55031621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 900, while the sum is 23.

The square root of 55031621 is about 7418.3300681488. The cubic root of 55031621 is about 380.3681128164.

Adding to 55031621 its reverse (12613055), we get a palindrome (67644676).

The spelling of 55031621 in words is "fifty-five million, thirty-one thousand, six hundred twenty-one".