20897915 has 8 divisors (see below), whose sum is σ = 26167968. Its totient is φ = 15991360.

The previous prime is 20897909. The next prime is 20897917. The reversal of 20897915 is 51979802.

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

It is not a de Polignac number, because 20897915 - 2²² = 16703611 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20897917) 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, 90746 + ... + 90975.

It is an arithmetic number, because the mean of its divisors is an integer number (3270996).

Almost surely, 2^20897915 is an apocalyptic number.

20897915 is a deficient number, since it is larger than the sum of its proper divisors (5270053).

20897915 is a wasteful number, since it uses less digits than its factorization.

20897915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181749.

The product of its (nonzero) digits is 45360, while the sum is 41.

The square root of 20897915 is about 4571.4237388367. The cubic root of 20897915 is about 275.4446360709. Note that the first 3 decimals are identical.

It can be divided in two parts, 20897 and 915, that added together give a palindrome (21812).

The spelling of 20897915 in words is "twenty million, eight hundred ninety-seven thousand, nine hundred fifteen".