21918348 has 18 divisors (see below), whose sum is σ = 55404804. Its totient is φ = 7306104.

The previous prime is 21918329. The next prime is 21918353. The reversal of 21918348 is 84381912.

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 608843 = 21918348 / (2 + 1 + 9 + 1 + 8 + 3 + 4 + 8).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 304386 + ... + 304457.

Almost surely, 2^21918348 is an apocalyptic number.

It is an amenable number.

21918348 is an abundant number, since it is smaller than the sum of its proper divisors (33486456).

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

21918348 is a wasteful number, since it uses less digits than its factorization.

21918348 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 608853 (or 608848 counting only the distinct ones).

The product of its digits is 13824, while the sum is 36.

The square root of 21918348 is about 4681.7035361073. The cubic root of 21918348 is about 279.8568485943.

The spelling of 21918348 in words is "twenty-one million, nine hundred eighteen thousand, three hundred forty-eight".