21289015 has 16 divisors (see below), whose sum is σ = 29509920. Its totient is φ = 14571520.

The previous prime is 21289001. The next prime is 21289027. The reversal of 21289015 is 51098212.

It is not a de Polignac number, because 21289015 - 2⁵ = 21288983 is a prime.

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, 10450 + ... + 12319.

It is an arithmetic number, because the mean of its divisors is an integer number (1844370).

Almost surely, 2^21289015 is an apocalyptic number.

21289015 is a deficient number, since it is larger than the sum of its proper divisors (8220905).

21289015 is a wasteful number, since it uses less digits than its factorization.

21289015 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22802.

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 21289015 is about 4614.0020589506. The cubic root of 21289015 is about 277.1523227438.

The spelling of 21289015 in words is "twenty-one million, two hundred eighty-nine thousand, fifteen".