20879391 has 16 divisors (see below), whose sum is σ = 31016160. Its totient is φ = 12405120.

The previous prime is 20879389. The next prime is 20879401. The reversal of 20879391 is 19397802.

It is not a de Polignac number, because 20879391 - 2¹ = 20879389 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20879321) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8100 + ... + 10361.

It is an arithmetic number, because the mean of its divisors is an integer number (1938510).

Almost surely, 2^20879391 is an apocalyptic number.

20879391 is a deficient number, since it is larger than the sum of its proper divisors (10136769).

20879391 is a wasteful number, since it uses less digits than its factorization.

20879391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18506.

The product of its (nonzero) digits is 27216, while the sum is 39.

The square root of 20879391 is about 4569.3972250178. The cubic root of 20879391 is about 275.3632269166.

The spelling of 20879391 in words is "twenty million, eight hundred seventy-nine thousand, three hundred ninety-one".