21012479 has 4 divisors (see below), whose sum is σ = 21029280. Its totient is φ = 20995680.

The previous prime is 21012457. The next prime is 21012503. The reversal of 21012479 is 97421012.

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 21012479 - 2¹⁶ = 20946943 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 (21012419) 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, 6359 + ... + 9080.

It is an arithmetic number, because the mean of its divisors is an integer number (5257320).

Almost surely, 2^21012479 is an apocalyptic number.

21012479 is a deficient number, since it is larger than the sum of its proper divisors (16801).

21012479 is a wasteful number, since it uses less digits than its factorization.

21012479 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16800.

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 21012479 is about 4583.9370632678. The cubic root of 21012479 is about 275.9470554118.

The spelling of 21012479 in words is "twenty-one million, twelve thousand, four hundred seventy-nine".