691215139091 has 2 divisors, whose sum is σ = 691215139092. Its totient is φ = 691215139090.

The previous prime is 691215139073. The next prime is 691215139099. The reversal of 691215139091 is 190931512196.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 691215139091 - 2¹⁴ = 691215122707 is a prime.

It is not a weakly prime, because it can be changed into another prime (691215139099) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345607569545 + 345607569546.

It is an arithmetic number, because the mean of its divisors is an integer number (345607569546).

Almost surely, 2^691215139091 is an apocalyptic number.

691215139091 is a deficient number, since it is larger than the sum of its proper divisors (1).

691215139091 is an equidigital number, since it uses as much as digits as its factorization.

691215139091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 131220, while the sum is 47.

The spelling of 691215139091 in words is "six hundred ninety-one billion, two hundred fifteen million, one hundred thirty-nine thousand, ninety-one".