21018896 has 30 divisors (see below), whose sum is σ = 41951742. Its totient is φ = 10195840.

The previous prime is 21018869. The next prime is 21018929. The reversal of 21018896 is 69881012.

It can be written as a sum of positive squares in only one way, i.e., 12816400 + 8202496 = 3580^2 + 2864^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 117335 + ... + 117513.

Almost surely, 2^21018896 is an apocalyptic number.

It is an amenable number.

21018896 is a deficient number, since it is larger than the sum of its proper divisors (20932846).

21018896 is an equidigital number, since it uses as much as digits as its factorization.

21018896 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 407 (or 222 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 35.

The square root of 21018896 is about 4584.6369540019. The cubic root of 21018896 is about 275.9751430390.

The spelling of 21018896 in words is "twenty-one million, eighteen thousand, eight hundred ninety-six".