21413888 has 30 divisors (see below), whose sum is σ = 42859236. Its totient is φ = 10698752.

The previous prime is 21413881. The next prime is 21413891. The reversal of 21413888 is 88831412.

It is not an unprimeable number, because it can be changed into a prime (21413881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15731 + ... + 17037.

Almost surely, 2^21413888 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21413888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21429618).

21413888 is an abundant number, since it is smaller than the sum of its proper divisors (21445348).

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

21413888 is an frugal number, since it uses more digits than its factorization.

21413888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1335 (or 1309 counting only the distinct ones).

The product of its digits is 12288, while the sum is 35.

The square root of 21413888 is about 4627.5142355265. The cubic root of 21413888 is about 277.6931555685.

The spelling of 21413888 in words is "twenty-one million, four hundred thirteen thousand, eight hundred eighty-eight".