21431479 has 4 divisors (see below), whose sum is σ = 21954240. Its totient is φ = 20908720.

The previous prime is 21431401. The next prime is 21431489. The reversal of 21431479 is 97413412.

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 21431479 - 2¹³ = 21423287 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21431479.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21431489) 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, 261319 + ... + 261400.

It is an arithmetic number, because the mean of its divisors is an integer number (5488560).

Almost surely, 2^21431479 is an apocalyptic number.

21431479 is a deficient number, since it is larger than the sum of its proper divisors (522761).

21431479 is an equidigital number, since it uses as much as digits as its factorization.

21431479 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 522760.

The product of its digits is 6048, while the sum is 31.

The square root of 21431479 is about 4629.4145418184. The cubic root of 21431479 is about 277.7691741987.

The spelling of 21431479 in words is "twenty-one million, four hundred thirty-one thousand, four hundred seventy-nine".