3656438021 has 2 divisors, whose sum is σ = 3656438022. Its totient is φ = 3656438020.

The previous prime is 3656437987. The next prime is 3656438029. The reversal of 3656438021 is 1208346563.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2016997921 + 1639440100 = 44911^2 + 40490^2 .

It is a cyclic number.

It is not a de Polignac number, because 3656438021 - 2¹⁰ = 3656436997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3656438029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1828219010 + 1828219011.

It is an arithmetic number, because the mean of its divisors is an integer number (1828219011).

Almost surely, 2^3656438021 is an apocalyptic number.

It is an amenable number.

3656438021 is a deficient number, since it is larger than the sum of its proper divisors (1).

3656438021 is an equidigital number, since it uses as much as digits as its factorization.

3656438021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 103680, while the sum is 38.

The square root of 3656438021 is about 60468.4878345738. The cubic root of 3656438021 is about 1540.5864440186.

The spelling of 3656438021 in words is "three billion, six hundred fifty-six million, four hundred thirty-eight thousand, twenty-one".