21023479 has 4 divisors (see below), whose sum is σ = 21145176. Its totient is φ = 20901784.

The previous prime is 21023473. The next prime is 21023501. The reversal of 21023479 is 97432012.

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 21023479 - 2¹¹ = 21021431 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 (21023473) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 60589 + ... + 60934.

It is an arithmetic number, because the mean of its divisors is an integer number (5286294).

Almost surely, 2^21023479 is an apocalyptic number.

21023479 is a deficient number, since it is larger than the sum of its proper divisors (121697).

21023479 is a wasteful number, since it uses less digits than its factorization.

21023479 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121696.

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 21023479 is about 4585.1367482334. The cubic root of 21023479 is about 275.9951996295.

The spelling of 21023479 in words is "twenty-one million, twenty-three thousand, four hundred seventy-nine".