21764315 has 4 divisors (see below), whose sum is σ = 26117184. Its totient is φ = 17411448.

The previous prime is 21764299. The next prime is 21764341. The reversal of 21764315 is 51346712.

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 21764315 - 2⁴ = 21764299 is a prime.

It is a Duffinian 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, 2176427 + ... + 2176436.

It is an arithmetic number, because the mean of its divisors is an integer number (6529296).

Almost surely, 2^21764315 is an apocalyptic number.

21764315 is a deficient number, since it is larger than the sum of its proper divisors (4352869).

21764315 is an equidigital number, since it uses as much as digits as its factorization.

21764315 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4352868.

The product of its digits is 5040, while the sum is 29.

The square root of 21764315 is about 4665.2240031964. The cubic root of 21764315 is about 279.1997345052.

The spelling of 21764315 in words is "twenty-one million, seven hundred sixty-four thousand, three hundred fifteen".