21471888 has 20 divisors (see below), whose sum is σ = 55469168. Its totient is φ = 7157280.

The previous prime is 21471883. The next prime is 21471899. The reversal of 21471888 is 88817412.

It is a happy number.

It is a super-2 number, since 2×21471888² = 922083948569088, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21471883) 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, 223618 + ... + 223713.

Almost surely, 2^21471888 is an apocalyptic number.

It is an amenable number.

21471888 is an abundant number, since it is smaller than the sum of its proper divisors (33997280).

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

21471888 is a wasteful number, since it uses less digits than its factorization.

21471888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 447342 (or 447336 counting only the distinct ones).

The product of its digits is 28672, while the sum is 39.

The square root of 21471888 is about 4633.7768612655. The cubic root of 21471888 is about 277.9436422857.

The spelling of 21471888 in words is "twenty-one million, four hundred seventy-one thousand, eight hundred eighty-eight".