691430287 has 2 divisors, whose sum is σ = 691430288. Its totient is φ = 691430286.

The previous prime is 691430227. The next prime is 691430309. The reversal of 691430287 is 782034196.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-691430287 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (691430227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345715143 + 345715144.

It is an arithmetic number, because the mean of its divisors is an integer number (345715144).

Almost surely, 2^691430287 is an apocalyptic number.

691430287 is a deficient number, since it is larger than the sum of its proper divisors (1).

691430287 is an equidigital number, since it uses as much as digits as its factorization.

691430287 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72576, while the sum is 40.

The square root of 691430287 is about 26295.0620269282. The cubic root of 691430287 is about 884.2657414284.

The spelling of 691430287 in words is "six hundred ninety-one million, four hundred thirty thousand, two hundred eighty-seven".