691919863 has 2 divisors, whose sum is σ = 691919864. Its totient is φ = 691919862.

The previous prime is 691919857. The next prime is 691919897. The reversal of 691919863 is 368919196.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 691919863 - 2⁵ = 691919831 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 691919863.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (691919803) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345959931 + 345959932.

It is an arithmetic number, because the mean of its divisors is an integer number (345959932).

Almost surely, 2^691919863 is an apocalyptic number.

691919863 is a deficient number, since it is larger than the sum of its proper divisors (1).

691919863 is an equidigital number, since it uses as much as digits as its factorization.

691919863 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 629856, while the sum is 52.

The square root of 691919863 is about 26304.3696560096. The cubic root of 691919863 is about 884.4743973868.

The spelling of 691919863 in words is "six hundred ninety-one million, nine hundred nineteen thousand, eight hundred sixty-three".