21998252 has 6 divisors (see below), whose sum is σ = 38496948. Its totient is φ = 10999124.

The previous prime is 21998243. The next prime is 21998267. The reversal of 21998252 is 25289912.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2749778 + ... + 2749785.

It is an arithmetic number, because the mean of its divisors is an integer number (6416158).

Almost surely, 2^21998252 is an apocalyptic number.

It is an amenable number.

21998252 is a deficient number, since it is larger than the sum of its proper divisors (16498696).

21998252 is a wasteful number, since it uses less digits than its factorization.

21998252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5499567 (or 5499565 counting only the distinct ones).

The product of its digits is 25920, while the sum is 38.

The square root of 21998252 is about 4690.2294186958. The cubic root of 21998252 is about 280.1965117103.

The spelling of 21998252 in words is "twenty-one million, nine hundred ninety-eight thousand, two hundred fifty-two".