21489215 has 16 divisors (see below), whose sum is σ = 28532736. Its totient is φ = 15405600.

The previous prime is 21489191. The next prime is 21489233. The reversal of 21489215 is 51298412.

It is not a de Polignac number, because 21489215 - 2⁶ = 21489151 is a prime.

It is a super-2 number, since 2×21489215² = 923572722632450, which contains 22 as substring.

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 15 ways as a sum of consecutive naturals, for example, 1154 + ... + 6656.

It is an arithmetic number, because the mean of its divisors is an integer number (1783296).

Almost surely, 2^21489215 is an apocalyptic number.

21489215 is a deficient number, since it is larger than the sum of its proper divisors (7043521).

21489215 is a wasteful number, since it uses less digits than its factorization.

21489215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5590.

The product of its digits is 5760, while the sum is 32.

The square root of 21489215 is about 4635.6461254069. The cubic root of 21489215 is about 278.0183855135.

The spelling of 21489215 in words is "twenty-one million, four hundred eighty-nine thousand, two hundred fifteen".