21407279 has 8 divisors (see below), whose sum is σ = 21901872. Its totient is φ = 20917440.

The previous prime is 21407263. The next prime is 21407293. The reversal of 21407279 is 97270412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21407279 - 2⁴ = 21407263 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 (21407179) 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 7 ways as a sum of consecutive naturals, for example, 8867 + ... + 11019.

It is an arithmetic number, because the mean of its divisors is an integer number (2737734).

Almost surely, 2^21407279 is an apocalyptic number.

21407279 is a deficient number, since it is larger than the sum of its proper divisors (494593).

21407279 is a wasteful number, since it uses less digits than its factorization.

21407279 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2377.

The product of its (nonzero) digits is 7056, while the sum is 32.

The square root of 21407279 is about 4626.8000821302. The cubic root of 21407279 is about 277.6645843455.

The spelling of 21407279 in words is "twenty-one million, four hundred seven thousand, two hundred seventy-nine".