21489798 has 32 divisors (see below), whose sum is σ = 49357440. Its totient is φ = 6168960.

The previous prime is 21489791. The next prime is 21489799. The reversal of 21489798 is 89798412.

It is a super-2 number, since 2×21489798² = 923622836161608, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21489791) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7315 + ... + 9822.

It is an arithmetic number, because the mean of its divisors is an integer number (1542420).

Almost surely, 2^21489798 is an apocalyptic number.

21489798 is an abundant number, since it is smaller than the sum of its proper divisors (27867642).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21489798 is a wasteful number, since it uses less digits than its factorization.

21489798 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17172.

The product of its digits is 290304, while the sum is 48.

The square root of 21489798 is about 4635.7090072609. The cubic root of 21489798 is about 278.0208996933.

The spelling of 21489798 in words is "twenty-one million, four hundred eighty-nine thousand, seven hundred ninety-eight".