21489845 has 16 divisors (see below), whose sum is σ = 27941760. Its totient is φ = 15772224.

The previous prime is 21489833. The next prime is 21489877. The reversal of 21489845 is 54898412.

It is not a de Polignac number, because 21489845 - 2⁴ = 21489829 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, 10712 + ... + 12558.

It is an arithmetic number, because the mean of its divisors is an integer number (1746360).

Almost surely, 2^21489845 is an apocalyptic number.

It is an amenable number.

21489845 is a deficient number, since it is larger than the sum of its proper divisors (6451915).

21489845 is a wasteful number, since it uses less digits than its factorization.

21489845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2044.

The product of its digits is 92160, while the sum is 41.

The square root of 21489845 is about 4635.7140766014. The cubic root of 21489845 is about 278.0211023782.

The spelling of 21489845 in words is "twenty-one million, four hundred eighty-nine thousand, eight hundred forty-five".