21521488 has 20 divisors (see below), whose sum is σ = 42586560. Its totient is φ = 10531424.

The previous prime is 21521483. The next prime is 21521503. The reversal of 21521488 is 88412512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21521483) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13558 + ... + 15061.

It is an arithmetic number, because the mean of its divisors is an integer number (2129328).

Almost surely, 2^21521488 is an apocalyptic number.

It is an amenable number.

21521488 is a deficient number, since it is larger than the sum of its proper divisors (21065072).

21521488 is a wasteful number, since it uses less digits than its factorization.

21521488 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28674 (or 28668 counting only the distinct ones).

The product of its digits is 5120, while the sum is 31.

The square root of 21521488 is about 4639.1257797132. The cubic root of 21521488 is about 278.1574940447.

The spelling of 21521488 in words is "twenty-one million, five hundred twenty-one thousand, four hundred eighty-eight".