20973215 has 4 divisors (see below), whose sum is σ = 25167864. Its totient is φ = 16778568.

The previous prime is 20973179. The next prime is 20973229. The reversal of 20973215 is 51237902.

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 20973215 - 2¹² = 20969119 is a prime.

It is a Duffinian number.

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, 2097317 + ... + 2097326.

It is an arithmetic number, because the mean of its divisors is an integer number (6291966).

Almost surely, 2^20973215 is an apocalyptic number.

20973215 is a deficient number, since it is larger than the sum of its proper divisors (4194649).

20973215 is an equidigital number, since it uses as much as digits as its factorization.

20973215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4194648.

The product of its (nonzero) digits is 3780, while the sum is 29.

The square root of 20973215 is about 4579.6522793767. The cubic root of 20973215 is about 275.7750696625.

The spelling of 20973215 in words is "twenty million, nine hundred seventy-three thousand, two hundred fifteen".