691138958 has 8 divisors (see below), whose sum is σ = 1037961480. Its totient is φ = 345151800.

The previous prime is 691138949. The next prime is 691139069. The reversal of 691138958 is 859831196.

It is a happy number.

691138958 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 206768 + ... + 210083.

It is an arithmetic number, because the mean of its divisors is an integer number (129745185).

Almost surely, 2^691138958 is an apocalyptic number.

691138958 is a deficient number, since it is larger than the sum of its proper divisors (346822522).

691138958 is a wasteful number, since it uses less digits than its factorization.

691138958 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 417682.

The product of its digits is 466560, while the sum is 50.

The square root of 691138958 is about 26289.5218290482. The cubic root of 691138958 is about 884.1415310544.

The spelling of 691138958 in words is "six hundred ninety-one million, one hundred thirty-eight thousand, nine hundred fifty-eight".