691215139663 has 2 divisors, whose sum is σ = 691215139664. Its totient is φ = 691215139662.

The previous prime is 691215139631. The next prime is 691215139669. The reversal of 691215139663 is 366931512196.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 691215139663 - 2⁵ = 691215139631 is a prime.

It is a super-4 number, since 4×691215139663⁴ (a number of 48 digits) contains 4444 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 691215139663.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (691215139669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345607569831 + 345607569832.

It is an arithmetic number, because the mean of its divisors is an integer number (345607569832).

Almost surely, 2^691215139663 is an apocalyptic number.

691215139663 is a deficient number, since it is larger than the sum of its proper divisors (1).

691215139663 is an equidigital number, since it uses as much as digits as its factorization.

691215139663 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1574640, while the sum is 52.

The spelling of 691215139663 in words is "six hundred ninety-one billion, two hundred fifteen million, one hundred thirty-nine thousand, six hundred sixty-three".