21464215 has 8 divisors (see below), whose sum is σ = 26067888. Its totient is φ = 16964160.

The previous prime is 21464213. The next prime is 21464227. The reversal of 21464215 is 51246412.

It is a happy number.

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

It is not a de Polignac number, because 21464215 - 2¹ = 21464213 is a prime.

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 21464215.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21464213) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25446 + ... + 26275.

It is an arithmetic number, because the mean of its divisors is an integer number (3258486).

Almost surely, 2^21464215 is an apocalyptic number.

21464215 is a deficient number, since it is larger than the sum of its proper divisors (4603673).

21464215 is an equidigital number, since it uses as much as digits as its factorization.

21464215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51809.

The product of its digits is 1920, while the sum is 25.

The square root of 21464215 is about 4632.9488449583. The cubic root of 21464215 is about 277.9105305312.

The spelling of 21464215 in words is "twenty-one million, four hundred sixty-four thousand, two hundred fifteen".