3939220921 has 2 divisors, whose sum is σ = 3939220922. Its totient is φ = 3939220920.

The previous prime is 3939220877. The next prime is 3939220937. The reversal of 3939220921 is 1290229393.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3530736400 + 408484521 = 59420^2 + 20211^2 .

It is a cyclic number.

It is not a de Polignac number, because 3939220921 - 2⁹ = 3939220409 is a prime.

It is a super-2 number, since 2×3939220921² = 31034922928888176482, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (3939220951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1969610460 + 1969610461.

It is an arithmetic number, because the mean of its divisors is an integer number (1969610461).

Almost surely, 2^3939220921 is an apocalyptic number.

It is an amenable number.

3939220921 is a deficient number, since it is larger than the sum of its proper divisors (1).

3939220921 is an equidigital number, since it uses as much as digits as its factorization.

3939220921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 52488, while the sum is 40.

The square root of 3939220921 is about 62763.2131188326. The cubic root of 3939220921 is about 1579.3199178830.

The spelling of 3939220921 in words is "three billion, nine hundred thirty-nine million, two hundred twenty thousand, nine hundred twenty-one".