20861879 has 4 divisors (see below), whose sum is σ = 20977320. Its totient is φ = 20746440.

The previous prime is 20861833. The next prime is 20861891. The reversal of 20861879 is 97816802.

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 20861879 - 2⁸ = 20861623 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 (20861809) 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, 57449 + ... + 57810.

It is an arithmetic number, because the mean of its divisors is an integer number (5244330).

Almost surely, 2^20861879 is an apocalyptic number.

20861879 is a deficient number, since it is larger than the sum of its proper divisors (115441).

20861879 is a wasteful number, since it uses less digits than its factorization.

20861879 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115440.

The product of its (nonzero) digits is 48384, while the sum is 41.

The square root of 20861879 is about 4567.4805965652. The cubic root of 20861879 is about 275.2862210050.

The spelling of 20861879 in words is "twenty million, eight hundred sixty-one thousand, eight hundred seventy-nine".