687398431 has 2 divisors, whose sum is σ = 687398432. Its totient is φ = 687398430.

The previous prime is 687398423. The next prime is 687398443. The reversal of 687398431 is 134893786.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 687398431 - 2³ = 687398423 is a prime.

It is a super-2 number, since 2×687398431² = 945033205882523522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (687398461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343699215 + 343699216.

It is an arithmetic number, because the mean of its divisors is an integer number (343699216).

Almost surely, 2^687398431 is an apocalyptic number.

687398431 is a deficient number, since it is larger than the sum of its proper divisors (1).

687398431 is an equidigital number, since it uses as much as digits as its factorization.

687398431 is an evil number, because the sum of its binary digits is even.

The product of its digits is 870912, while the sum is 49.

The square root of 687398431 is about 26218.2842878782. The cubic root of 687398431 is about 882.5436181819.

The spelling of 687398431 in words is "six hundred eighty-seven million, three hundred ninety-eight thousand, four hundred thirty-one".