6402391 has 2 divisors, whose sum is σ = 6402392. Its totient is φ = 6402390.

The previous prime is 6402379. The next prime is 6402401. The reversal of 6402391 is 1932046.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6402391 is a prime.

It is a super-2 number, since 2×6402391² = 81981221033762, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6402311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3201195 + 3201196.

It is an arithmetic number, because the mean of its divisors is an integer number (3201196).

Almost surely, 2^6402391 is an apocalyptic number.

6402391 is a deficient number, since it is larger than the sum of its proper divisors (1).

6402391 is an equidigital number, since it uses as much as digits as its factorization.

6402391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1296, while the sum is 25.

The square root of 6402391 is about 2530.2946468742. The cubic root of 6402391 is about 185.6866713802.

The spelling of 6402391 in words is "six million, four hundred two thousand, three hundred ninety-one".