21253888 has 18 divisors (see below), whose sum is σ = 42425264. Its totient is φ = 10626816.

The previous prime is 21253871. The next prime is 21253889. The reversal of 21253888 is 88835212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21253889) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41256 + ... + 41767.

Almost surely, 2^21253888 is an apocalyptic number.

It is an amenable number.

21253888 is a deficient number, since it is larger than the sum of its proper divisors (21171376).

21253888 is an frugal number, since it uses more digits than its factorization.

21253888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83039 (or 83025 counting only the distinct ones).

The product of its digits is 30720, while the sum is 37.

The square root of 21253888 is about 4610.1939221686. The cubic root of 21253888 is about 276.9998045066. Note that the first 3 decimals are identical.

The spelling of 21253888 in words is "twenty-one million, two hundred fifty-three thousand, eight hundred eighty-eight".