21053315 has 8 divisors (see below), whose sum is σ = 25307808. Its totient is φ = 16813440.

The previous prime is 21053299. The next prime is 21053323. The reversal of 21053315 is 51335012.

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

It is not a de Polignac number, because 21053315 - 2⁴ = 21053299 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 182 + ... + 6491.

It is an arithmetic number, because the mean of its divisors is an integer number (3163476).

Almost surely, 2^21053315 is an apocalyptic number.

21053315 is a deficient number, since it is larger than the sum of its proper divisors (4254493).

21053315 is an equidigital number, since it uses as much as digits as its factorization.

21053315 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7309.

The product of its (nonzero) digits is 450, while the sum is 20.

The square root of 21053315 is about 4588.3891508894. The cubic root of 21053315 is about 276.1256997622.

Adding to 21053315 its reverse (51335012), we get a palindrome (72388327).

The spelling of 21053315 in words is "twenty-one million, fifty-three thousand, three hundred fifteen".