687942457 has 2 divisors, whose sum is σ = 687942458. Its totient is φ = 687942456.

The previous prime is 687942433. The next prime is 687942461. The reversal of 687942457 is 754249786.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 446730496 + 241211961 = 21136^2 + 15531^2 .

It is a cyclic number.

It is not a de Polignac number, because 687942457 - 2²⁷ = 553724729 is a prime.

It is not a weakly prime, because it can be changed into another prime (687942427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343971228 + 343971229.

It is an arithmetic number, because the mean of its divisors is an integer number (343971229).

Almost surely, 2^687942457 is an apocalyptic number.

It is an amenable number.

687942457 is a deficient number, since it is larger than the sum of its proper divisors (1).

687942457 is an equidigital number, since it uses as much as digits as its factorization.

687942457 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3386880, while the sum is 52.

The square root of 687942457 is about 26228.6571711172. The cubic root of 687942457 is about 882.7763798751.

The spelling of 687942457 in words is "six hundred eighty-seven million, nine hundred forty-two thousand, four hundred fifty-seven".