21558442 has 8 divisors (see below), whose sum is σ = 32366016. Its totient is φ = 10769772.

The previous prime is 21558413. The next prime is 21558443. The reversal of 21558442 is 24485512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21558443) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1408 + ... + 6715.

It is an arithmetic number, because the mean of its divisors is an integer number (4045752).

Almost surely, 2^21558442 is an apocalyptic number.

21558442 is a deficient number, since it is larger than the sum of its proper divisors (10807574).

21558442 is a wasteful number, since it uses less digits than its factorization.

21558442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9452.

The product of its digits is 12800, while the sum is 31.

The square root of 21558442 is about 4643.1069339398. The cubic root of 21558442 is about 278.3166087297.

The spelling of 21558442 in words is "twenty-one million, five hundred fifty-eight thousand, four hundred forty-two".