39402421 has 2 divisors, whose sum is σ = 39402422. Its totient is φ = 39402420.

The previous prime is 39402367. The next prime is 39402431. The reversal of 39402421 is 12420493.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31640625 + 7761796 = 5625^2 + 2786^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-39402421 is a prime.

It is a super-2 number, since 2×39402421² = 3105101561322482, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (39402431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19701210 + 19701211.

It is an arithmetic number, because the mean of its divisors is an integer number (19701211).

Almost surely, 2^39402421 is an apocalyptic number.

It is an amenable number.

39402421 is a deficient number, since it is larger than the sum of its proper divisors (1).

39402421 is an equidigital number, since it uses as much as digits as its factorization.

39402421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 39402421 is about 6277.1347763132. The cubic root of 39402421 is about 340.2835610214.

The spelling of 39402421 in words is "thirty-nine million, four hundred two thousand, four hundred twenty-one".