21294988 has 48 divisors (see below), whose sum is σ = 44593920. Its totient is φ = 8769600.

The previous prime is 21294937. The next prime is 21294989. The reversal of 21294988 is 88949212.

It is not an unprimeable number, because it can be changed into a prime (21294989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 33433 + ... + 34063.

It is an arithmetic number, because the mean of its divisors is an integer number (929040).

Almost surely, 2^21294988 is an apocalyptic number.

It is an amenable number.

21294988 is an abundant number, since it is smaller than the sum of its proper divisors (23298932).

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

21294988 is a wasteful number, since it uses less digits than its factorization.

21294988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 718 (or 716 counting only the distinct ones).

The product of its digits is 82944, while the sum is 43.

The square root of 21294988 is about 4614.6492824482. The cubic root of 21294988 is about 277.1782402734.

It can be divided in two parts, 2129 and 4988, that added together give a palindrome (7117).

The spelling of 21294988 in words is "twenty-one million, two hundred ninety-four thousand, nine hundred eighty-eight".