21464239 has 2 divisors, whose sum is σ = 21464240. Its totient is φ = 21464238.

The previous prime is 21464227. The next prime is 21464249. The reversal of 21464239 is 93246412.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21464239 - 2⁵ = 21464207 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21464239.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21464249) 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 as a sum of consecutive naturals, namely, 10732119 + 10732120.

It is an arithmetic number, because the mean of its divisors is an integer number (10732120).

Almost surely, 2^21464239 is an apocalyptic number.

21464239 is a deficient number, since it is larger than the sum of its proper divisors (1).

21464239 is an equidigital number, since it uses as much as digits as its factorization.

21464239 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10368, while the sum is 31.

The square root of 21464239 is about 4632.9514351005. The cubic root of 21464239 is about 277.9106341122.

It can be divided in two parts, 214 and 64239, that multiplied together give a triangular number (13747146 = T₅₂₄₃).

The spelling of 21464239 in words is "twenty-one million, four hundred sixty-four thousand, two hundred thirty-nine".