691133121 has 32 divisors (see below), whose sum is σ = 1186225920. Its totient is φ = 389515392.

The previous prime is 691133119. The next prime is 691133137. The reversal of 691133121 is 121331196.

It is not a de Polignac number, because 691133121 - 2¹ = 691133119 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (691133161) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11250 + ... + 38843.

It is an arithmetic number, because the mean of its divisors is an integer number (37069560).

Almost surely, 2^691133121 is an apocalyptic number.

It is an amenable number.

691133121 is a deficient number, since it is larger than the sum of its proper divisors (495092799).

691133121 is a wasteful number, since it uses less digits than its factorization.

691133121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50182 (or 50176 counting only the distinct ones).

The product of its digits is 972, while the sum is 27.

The square root of 691133121 is about 26289.4108150031. The cubic root of 691133121 is about 884.1390420476.

The spelling of 691133121 in words is "six hundred ninety-one million, one hundred thirty-three thousand, one hundred twenty-one".