879840021 has 16 divisors (see below), whose sum is σ = 1184198400. Its totient is φ = 581047488.

The previous prime is 879840007. The next prime is 879840041. The reversal of 879840021 is 120048978.

It is not a de Polignac number, because 879840021 - 2¹³ = 879831829 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (879840041) 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, 138135 + ... + 144363.

It is an arithmetic number, because the mean of its divisors is an integer number (74012400).

Almost surely, 2^879840021 is an apocalyptic number.

It is an amenable number.

879840021 is a deficient number, since it is larger than the sum of its proper divisors (304358379).

879840021 is a wasteful number, since it uses less digits than its factorization.

879840021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6668.

The product of its (nonzero) digits is 32256, while the sum is 39.

The square root of 879840021 is about 29662.0973803270. The cubic root of 879840021 is about 958.2258976995.

Adding to 879840021 its reverse (120048978), we get a palindrome (999888999).

The spelling of 879840021 in words is "eight hundred seventy-nine million, eight hundred forty thousand, twenty-one".