690655687 has 2 divisors, whose sum is σ = 690655688. Its totient is φ = 690655686.

The previous prime is 690655673. The next prime is 690655697. The reversal of 690655687 is 786556096.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-690655687 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (690655607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345327843 + 345327844.

It is an arithmetic number, because the mean of its divisors is an integer number (345327844).

Almost surely, 2^690655687 is an apocalyptic number.

690655687 is a deficient number, since it is larger than the sum of its proper divisors (1).

690655687 is an equidigital number, since it uses as much as digits as its factorization.

690655687 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2721600, while the sum is 52.

The square root of 690655687 is about 26280.3288982463. The cubic root of 690655687 is about 883.9354077243.

The spelling of 690655687 in words is "six hundred ninety million, six hundred fifty-five thousand, six hundred eighty-seven".