39913921 has 2 divisors, whose sum is σ = 39913922. Its totient is φ = 39913920.

The previous prime is 39913903. The next prime is 39913931. The reversal of 39913921 is 12931993.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 34339600 + 5574321 = 5860^2 + 2361^2 .

It is a cyclic number.

It is not a de Polignac number, because 39913921 - 2⁷ = 39913793 is a prime.

It is not a weakly prime, because it can be changed into another prime (39913931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19956960 + 19956961.

It is an arithmetic number, because the mean of its divisors is an integer number (19956961).

Almost surely, 2^39913921 is an apocalyptic number.

It is an amenable number.

39913921 is a deficient number, since it is larger than the sum of its proper divisors (1).

39913921 is an equidigital number, since it uses as much as digits as its factorization.

39913921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13122, while the sum is 37.

The square root of 39913921 is about 6317.7465128003. The cubic root of 39913921 is about 341.7496914501.

The spelling of 39913921 in words is "thirty-nine million, nine hundred thirteen thousand, nine hundred twenty-one".