21544379 has 4 divisors (see below), whose sum is σ = 21766584. Its totient is φ = 21322176.

The previous prime is 21544373. The next prime is 21544403. The reversal of 21544379 is 97344512.

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 21544379 - 2⁴ = 21544363 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21544373) 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, 110957 + ... + 111150.

It is an arithmetic number, because the mean of its divisors is an integer number (5441646).

Almost surely, 2^21544379 is an apocalyptic number.

21544379 is a deficient number, since it is larger than the sum of its proper divisors (222205).

21544379 is an equidigital number, since it uses as much as digits as its factorization.

21544379 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222204.

The product of its digits is 30240, while the sum is 35.

The square root of 21544379 is about 4641.5922914448. The cubic root of 21544379 is about 278.2560784151.

The spelling of 21544379 in words is "twenty-one million, five hundred forty-four thousand, three hundred seventy-nine".