691389131 has 16 divisors (see below), whose sum is σ = 745941504. Its totient is φ = 639201024.

The previous prime is 691389107. The next prime is 691389151. The reversal of 691389131 is 131983196.

691389131 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 691389131 - 2¹⁰ = 691388107 is a prime.

It is a super-2 number, since 2×691389131² = 956037860929870322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (691389151) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 92330 + ... + 99536.

It is an arithmetic number, because the mean of its divisors is an integer number (46621344).

Almost surely, 2^691389131 is an apocalyptic number.

691389131 is a deficient number, since it is larger than the sum of its proper divisors (54552373).

691389131 is a wasteful number, since it uses less digits than its factorization.

691389131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7370.

The product of its digits is 34992, while the sum is 41.

The square root of 691389131 is about 26294.2794348885. The cubic root of 691389131 is about 884.2481963658.

The spelling of 691389131 in words is "six hundred ninety-one million, three hundred eighty-nine thousand, one hundred thirty-one".