21374215 has 4 divisors (see below), whose sum is σ = 25649064. Its totient is φ = 17099368.

The previous prime is 21374209. The next prime is 21374231. The reversal of 21374215 is 51247312.

It is a happy number.

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 21374215 - 2¹¹ = 21372167 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 21374215.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2137417 + ... + 2137426.

It is an arithmetic number, because the mean of its divisors is an integer number (6412266).

Almost surely, 2^21374215 is an apocalyptic number.

21374215 is a deficient number, since it is larger than the sum of its proper divisors (4274849).

21374215 is an equidigital number, since it uses as much as digits as its factorization.

21374215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4274848.

The product of its digits is 1680, while the sum is 25.

The square root of 21374215 is about 4623.2256055702. The cubic root of 21374215 is about 277.5215577225.

The spelling of 21374215 in words is "twenty-one million, three hundred seventy-four thousand, two hundred fifteen".