21384279 has 12 divisors (see below), whose sum is σ = 35301136. Its totient is φ = 12219552.

The previous prime is 21384263. The next prime is 21384289. The reversal of 21384279 is 97248312.

21384279 is a `hidden beast` number, since 2 + 1 + 384 + 279 = 666.

It is not a de Polignac number, because 21384279 - 2⁴ = 21384263 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 (21384229) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 169654 + ... + 169779.

Almost surely, 2^21384279 is an apocalyptic number.

21384279 is a deficient number, since it is larger than the sum of its proper divisors (13916857).

21384279 is a wasteful number, since it uses less digits than its factorization.

21384279 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 339446 (or 339443 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 21384279 is about 4624.3138950551. The cubic root of 21384279 is about 277.5651076839.

The spelling of 21384279 in words is "twenty-one million, three hundred eighty-four thousand, two hundred seventy-nine".