861929879 has 4 divisors (see below), whose sum is σ = 876538920. Its totient is φ = 847320840.

The previous prime is 861929857. The next prime is 861929881. The reversal of 861929879 is 978929168.

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 861929879 - 2²⁴ = 845152663 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (59), and also a Moran number because the ratio is a prime number: 14608981 = 861929879 / (8 + 6 + 1 + 9 + 2 + 9 + 8 + 7 + 9).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861929779) 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, 7304432 + ... + 7304549.

It is an arithmetic number, because the mean of its divisors is an integer number (219134730).

Almost surely, 2^861929879 is an apocalyptic number.

861929879 is a deficient number, since it is larger than the sum of its proper divisors (14609041).

861929879 is a wasteful number, since it uses less digits than its factorization.

861929879 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14609040.

The product of its digits is 3919104, while the sum is 59.

The square root of 861929879 is about 29358.6423221511. The cubic root of 861929879 is about 951.6793487200.

The spelling of 861929879 in words is "eight hundred sixty-one million, nine hundred twenty-nine thousand, eight hundred seventy-nine".