3664256021 has 2 divisors, whose sum is σ = 3664256022. Its totient is φ = 3664256020.

The previous prime is 3664255999. The next prime is 3664256023. The reversal of 3664256021 is 1206524663.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3350788996 + 313467025 = 57886^2 + 17705^2 .

It is a cyclic number.

It is not a de Polignac number, because 3664256021 - 2⁶ = 3664255957 is a prime.

Together with 3664256023, 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 (3664256023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1832128010 + 1832128011.

It is an arithmetic number, because the mean of its divisors is an integer number (1832128011).

Almost surely, 2^3664256021 is an apocalyptic number.

It is an amenable number.

3664256021 is a deficient number, since it is larger than the sum of its proper divisors (1).

3664256021 is an equidigital number, since it uses as much as digits as its factorization.

3664256021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 51840, while the sum is 35.

The square root of 3664256021 is about 60533.0985577312. The cubic root of 3664256021 is about 1541.6836622011.

The spelling of 3664256021 in words is "three billion, six hundred sixty-four million, two hundred fifty-six thousand, twenty-one".