21243948 has 48 divisors (see below), whose sum is σ = 57262464. Its totient is φ = 6058240.

The previous prime is 21243941. The next prime is 21243977. The reversal of 21243948 is 84934212.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (21243941) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2490 + ... + 6977.

It is an arithmetic number, because the mean of its divisors is an integer number (1192968).

Almost surely, 2^21243948 is an apocalyptic number.

It is an amenable number.

21243948 is an abundant number, since it is smaller than the sum of its proper divisors (36018516).

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

21243948 is a wasteful number, since it uses less digits than its factorization.

21243948 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9502 (or 9500 counting only the distinct ones).

The product of its digits is 13824, while the sum is 33.

The square root of 21243948 is about 4609.1157503365. The cubic root of 21243948 is about 276.9566154299.

The spelling of 21243948 in words is "twenty-one million, two hundred forty-three thousand, nine hundred forty-eight".