21365880424 has 24 divisors (see below), whose sum is σ = 46601602290. Its totient is φ = 9156805728.

The previous prime is 21365880421. The next prime is 21365880439. The reversal of 21365880424 is 42408856312.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 14513020900 + 6852859524 = 120470^2 + 82782^2 .

It is not an unprimeable number, because it can be changed into a prime (21365880421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 27252007 + ... + 27252790.

Almost surely, 2^21365880424 is an apocalyptic number.

It is an amenable number.

21365880424 is an abundant number, since it is smaller than the sum of its proper divisors (25235721866).

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

21365880424 is a wasteful number, since it uses less digits than its factorization.

21365880424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54504817 (or 54504806 counting only the distinct ones).

The product of its (nonzero) digits is 368640, while the sum is 43.

The spelling of 21365880424 in words is "twenty-one billion, three hundred sixty-five million, eight hundred eighty thousand, four hundred twenty-four".