691879491 has 12 divisors (see below), whose sum is σ = 1042833168. Its totient is φ = 441198384.

The previous prime is 691879457. The next prime is 691879499. The reversal of 691879491 is 194978196.

It is not a de Polignac number, because 691879491 - 2¹⁵ = 691846723 is a prime.

It is not an unprimeable number, because it can be changed into a prime (691879499) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1671000 + ... + 1671413.

It is an arithmetic number, because the mean of its divisors is an integer number (86902764).

Almost surely, 2^691879491 is an apocalyptic number.

691879491 is a deficient number, since it is larger than the sum of its proper divisors (350953677).

691879491 is a wasteful number, since it uses less digits than its factorization.

691879491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3342442 (or 3342439 counting only the distinct ones).

The product of its digits is 979776, while the sum is 54.

The square root of 691879491 is about 26303.6022437992. The cubic root of 691879491 is about 884.4571946746.

The spelling of 691879491 in words is "six hundred ninety-one million, eight hundred seventy-nine thousand, four hundred ninety-one".