39157421 has 2 divisors, whose sum is σ = 39157422. Its totient is φ = 39157420.

The previous prime is 39157411. The next prime is 39157427. The reversal of 39157421 is 12475193.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 34975396 + 4182025 = 5914^2 + 2045^2 .

It is a cyclic number.

It is not a de Polignac number, because 39157421 - 2⁶ = 39157357 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (39157427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19578710 + 19578711.

It is an arithmetic number, because the mean of its divisors is an integer number (19578711).

Almost surely, 2^39157421 is an apocalyptic number.

It is an amenable number.

39157421 is a deficient number, since it is larger than the sum of its proper divisors (1).

39157421 is an equidigital number, since it uses as much as digits as its factorization.

39157421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7560, while the sum is 32.

The square root of 39157421 is about 6257.5890724783. The cubic root of 39157421 is about 339.5768120126.

The spelling of 39157421 in words is "thirty-nine million, one hundred fifty-seven thousand, four hundred twenty-one".