55720961 has 2 divisors, whose sum is σ = 55720962. Its totient is φ = 55720960.

The previous prime is 55720949. The next prime is 55720969. The reversal of 55720961 is 16902755.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 51394561 + 4326400 = 7169^2 + 2080^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55720961 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (55720969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27860480 + 27860481.

It is an arithmetic number, because the mean of its divisors is an integer number (27860481).

Almost surely, 2^55720961 is an apocalyptic number.

It is an amenable number.

55720961 is a deficient number, since it is larger than the sum of its proper divisors (1).

55720961 is an equidigital number, since it uses as much as digits as its factorization.

55720961 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18900, while the sum is 35.

The square root of 55720961 is about 7464.6474129727. The cubic root of 55720961 is about 381.9497229226.

The spelling of 55720961 in words is "fifty-five million, seven hundred twenty thousand, nine hundred sixty-one".