691088371 has 2 divisors, whose sum is σ = 691088372. Its totient is φ = 691088370.

The previous prime is 691088353. The next prime is 691088441. The reversal of 691088371 is 173880196.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-691088371 is a prime.

It is not a weakly prime, because it can be changed into another prime (691088341) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345544185 + 345544186.

It is an arithmetic number, because the mean of its divisors is an integer number (345544186).

Almost surely, 2^691088371 is an apocalyptic number.

691088371 is a deficient number, since it is larger than the sum of its proper divisors (1).

691088371 is an equidigital number, since it uses as much as digits as its factorization.

691088371 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72576, while the sum is 43.

The square root of 691088371 is about 26288.5596980892. The cubic root of 691088371 is about 884.1199593389.

The spelling of 691088371 in words is "six hundred ninety-one million, eighty-eight thousand, three hundred seventy-one".