21123888 has 40 divisors (see below), whose sum is σ = 55502400. Its totient is φ = 6921024.

The previous prime is 21123887. The next prime is 21123899. The reversal of 21123888 is 88832112.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (21123887) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 898 + ... + 6561.

It is an arithmetic number, because the mean of its divisors is an integer number (1387560).

Almost surely, 2^21123888 is an apocalyptic number.

It is an amenable number.

21123888 is an abundant number, since it is smaller than the sum of its proper divisors (34378512).

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

21123888 is a wasteful number, since it uses less digits than its factorization.

21123888 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7529 (or 7523 counting only the distinct ones).

The product of its digits is 6144, while the sum is 33.

The square root of 21123888 is about 4596.0731064682. The cubic root of 21123888 is about 276.4338901076.

The spelling of 21123888 in words is "twenty-one million, one hundred twenty-three thousand, eight hundred eighty-eight".