21879273 has 16 divisors (see below), whose sum is σ = 32431616. Its totient is φ = 13029120.

The previous prime is 21879271. The next prime is 21879307. The reversal of 21879273 is 37297812.

It is not a de Polignac number, because 21879273 - 2¹ = 21879271 is a prime.

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

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21879271) 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, 7840 + ... + 10257.

It is an arithmetic number, because the mean of its divisors is an integer number (2026976).

Almost surely, 2^21879273 is an apocalyptic number.

It is an amenable number.

21879273 is a deficient number, since it is larger than the sum of its proper divisors (10552343).

21879273 is a wasteful number, since it uses less digits than its factorization.

21879273 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18144.

The product of its digits is 42336, while the sum is 39.

The square root of 21879273 is about 4677.5285140766. The cubic root of 21879273 is about 279.6904444599.

The spelling of 21879273 in words is "twenty-one million, eight hundred seventy-nine thousand, two hundred seventy-three".