691412639 has 2 divisors, whose sum is σ = 691412640. Its totient is φ = 691412638.

The previous prime is 691412633. The next prime is 691412651. The reversal of 691412639 is 936214196.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 691412639 - 2⁸ = 691412383 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 691412596 and 691412605.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (691412633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345706319 + 345706320.

It is an arithmetic number, because the mean of its divisors is an integer number (345706320).

Almost surely, 2^691412639 is an apocalyptic number.

691412639 is a deficient number, since it is larger than the sum of its proper divisors (1).

691412639 is an equidigital number, since it uses as much as digits as its factorization.

691412639 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 69984, while the sum is 41.

The square root of 691412639 is about 26294.7264484725. The cubic root of 691412639 is about 884.2582180598.

The spelling of 691412639 in words is "six hundred ninety-one million, four hundred twelve thousand, six hundred thirty-nine".