21818424 has 32 divisors (see below), whose sum is σ = 55092240. Its totient is φ = 7200000.

The previous prime is 21818417. The next prime is 21818431. The reversal of 21818424 is 42481812.

It is an interprime number because it is at equal distance from previous prime (21818417) and next prime (21818431).

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

It is a junction number, because it is equal to n+sod(n) for n = 21818391 and 21818400.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2077 + ... + 6924.

Almost surely, 2^21818424 is an apocalyptic number.

21818424 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21818424 is an abundant number, since it is smaller than the sum of its proper divisors (33273816).

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

21818424 is a wasteful number, since it uses less digits than its factorization.

21818424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9111 (or 9107 counting only the distinct ones).

The product of its digits is 4096, while the sum is 30.

The square root of 21818424 is about 4671.0195889120. The cubic root of 21818424 is about 279.4309189950.

The spelling of 21818424 in words is "twenty-one million, eight hundred eighteen thousand, four hundred twenty-four".