21142320 has 40 divisors (see below), whose sum is σ = 65541936. Its totient is φ = 5637888.

The previous prime is 21142291. The next prime is 21142343. The reversal of 21142320 is 2324112.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21142320.

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, 43807 + ... + 44286.

Almost surely, 2^21142320 is an apocalyptic number.

21142320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21142320 is an abundant number, since it is smaller than the sum of its proper divisors (44399616).

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

21142320 is a wasteful number, since it uses less digits than its factorization.

21142320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88109 (or 88103 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 21142320 is about 4598.0778592799. The cubic root of 21142320 is about 276.5142690638.

Adding to 21142320 its reverse (2324112), we get a palindrome (23466432).

The spelling of 21142320 in words is "twenty-one million, one hundred forty-two thousand, three hundred twenty".