21642158 has 8 divisors (see below), whose sum is σ = 33218328. Its totient is φ = 10569384.

The previous prime is 21642143. The next prime is 21642169. The reversal of 21642158 is 85124612.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21642158.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 125741 + ... + 125912.

It is an arithmetic number, because the mean of its divisors is an integer number (4152291).

Almost surely, 2^21642158 is an apocalyptic number.

21642158 is a deficient number, since it is larger than the sum of its proper divisors (11576170).

21642158 is a wasteful number, since it uses less digits than its factorization.

21642158 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 251698.

The product of its digits is 3840, while the sum is 29.

The square root of 21642158 is about 4652.1132832295. The cubic root of 21642158 is about 278.6763975474.

The spelling of 21642158 in words is "twenty-one million, six hundred forty-two thousand, one hundred fifty-eight".