3638656221 has 4 divisors (see below), whose sum is σ = 4851541632. Its totient is φ = 2425770812.

The previous prime is 3638656171. The next prime is 3638656243. The reversal of 3638656221 is 1226568363.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 3638656221 - 2⁶ = 3638656157 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3638656261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 606442701 + ... + 606442706.

It is an arithmetic number, because the mean of its divisors is an integer number (1212885408).

Almost surely, 2^3638656221 is an apocalyptic number.

It is an amenable number.

3638656221 is a deficient number, since it is larger than the sum of its proper divisors (1212885411).

3638656221 is a wasteful number, since it uses less digits than its factorization.

3638656221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1212885410.

The product of its digits is 311040, while the sum is 42.

The square root of 3638656221 is about 60321.2750279700. The cubic root of 3638656221 is about 1538.0850179570.

The spelling of 3638656221 in words is "three billion, six hundred thirty-eight million, six hundred fifty-six thousand, two hundred twenty-one".