691110631 has 2 divisors, whose sum is σ = 691110632. Its totient is φ = 691110630.

The previous prime is 691110569. The next prime is 691110643. The reversal of 691110631 is 136011196.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 691110631 - 2¹³ = 691102439 is a prime.

It is a super-2 number, since 2×691110631² = 955267808562436322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 691110631.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (691110661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345555315 + 345555316.

It is an arithmetic number, because the mean of its divisors is an integer number (345555316).

Almost surely, 2^691110631 is an apocalyptic number.

691110631 is a deficient number, since it is larger than the sum of its proper divisors (1).

691110631 is an equidigital number, since it uses as much as digits as its factorization.

691110631 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 972, while the sum is 28.

The square root of 691110631 is about 26288.9830727626. The cubic root of 691110631 is about 884.1294517568.

The spelling of 691110631 in words is "six hundred ninety-one million, one hundred ten thousand, six hundred thirty-one".