21489788 has 12 divisors (see below), whose sum is σ = 37676352. Its totient is φ = 10725120.

The previous prime is 21489761. The next prime is 21489791. The reversal of 21489788 is 88798412.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2348 + ... + 6963.

It is an arithmetic number, because the mean of its divisors is an integer number (3139696).

Almost surely, 2^21489788 is an apocalyptic number.

It is an amenable number.

21489788 is a deficient number, since it is larger than the sum of its proper divisors (16186564).

21489788 is a wasteful number, since it uses less digits than its factorization.

21489788 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9892 (or 9890 counting only the distinct ones).

The product of its digits is 258048, while the sum is 47.

The square root of 21489788 is about 4635.7079286771. The cubic root of 21489788 is about 278.0208565689.

The spelling of 21489788 in words is "twenty-one million, four hundred eighty-nine thousand, seven hundred eighty-eight".