21553842 has 32 divisors (see below), whose sum is σ = 44029440. Its totient is φ = 7032960.

The previous prime is 21553837. The next prime is 21553843. The reversal of 21553842 is 24835512.

It is not an unprimeable number, because it can be changed into a prime (21553843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 96543 + ... + 96765.

It is an arithmetic number, because the mean of its divisors is an integer number (1375920).

Almost surely, 2^21553842 is an apocalyptic number.

21553842 is an abundant number, since it is smaller than the sum of its proper divisors (22475598).

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

21553842 is a wasteful number, since it uses less digits than its factorization.

21553842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 498.

The product of its digits is 9600, while the sum is 30.

The square root of 21553842 is about 4642.6115495484. The cubic root of 21553842 is about 278.2968121929.

The spelling of 21553842 in words is "twenty-one million, five hundred fifty-three thousand, eight hundred forty-two".