5656212721 has 2 divisors, whose sum is σ = 5656212722. Its totient is φ = 5656212720.

The previous prime is 5656212719. The next prime is 5656212763. The reversal of 5656212721 is 1272126565.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3571377121 + 2084835600 = 59761^2 + 45660^2 .

It is a cyclic number.

It is not a de Polignac number, because 5656212721 - 2¹ = 5656212719 is a prime.

Together with 5656212719, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (5656212701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2828106360 + 2828106361.

It is an arithmetic number, because the mean of its divisors is an integer number (2828106361).

Almost surely, 2^5656212721 is an apocalyptic number.

It is an amenable number.

5656212721 is a deficient number, since it is larger than the sum of its proper divisors (1).

5656212721 is an equidigital number, since it uses as much as digits as its factorization.

5656212721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 50400, while the sum is 37.

The square root of 5656212721 is about 75207.7969428702. The cubic root of 5656212721 is about 1781.7300774633.

The spelling of 5656212721 in words is "five billion, six hundred fifty-six million, two hundred twelve thousand, seven hundred twenty-one".