869601991 has 4 divisors (see below), whose sum is σ = 870080832. Its totient is φ = 869123152.

The previous prime is 869601983. The next prime is 869602007. The reversal of 869601991 is 199106968.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 869601991 - 2³ = 869601983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (869601961) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 236686 + ... + 240331.

It is an arithmetic number, because the mean of its divisors is an integer number (217520208).

Almost surely, 2^869601991 is an apocalyptic number.

869601991 is a deficient number, since it is larger than the sum of its proper divisors (478841).

869601991 is a wasteful number, since it uses less digits than its factorization.

869601991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 478840.

The product of its (nonzero) digits is 209952, while the sum is 49.

The square root of 869601991 is about 29489.0147512595. The cubic root of 869601991 is about 954.4946719417.

The spelling of 869601991 in words is "eight hundred sixty-nine million, six hundred one thousand, nine hundred ninety-one".