21859842 has 32 divisors (see below), whose sum is σ = 46238400. Its totient is φ = 6870528.

The previous prime is 21859837. The next prime is 21859843. The reversal of 21859842 is 24895812.

It is a self number, because there is not a number n which added to its sum of digits gives 21859842.

It is not an unprimeable number, because it can be changed into a prime (21859843) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38134 + ... + 38702.

It is an arithmetic number, because the mean of its divisors is an integer number (1444950).

Almost surely, 2^21859842 is an apocalyptic number.

21859842 is an abundant number, since it is smaller than the sum of its proper divisors (24378558).

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

21859842 is a wasteful number, since it uses less digits than its factorization.

21859842 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 930.

The product of its digits is 46080, while the sum is 39.

The square root of 21859842 is about 4675.4509942892. The cubic root of 21859842 is about 279.6076221671.

The spelling of 21859842 in words is "twenty-one million, eight hundred fifty-nine thousand, eight hundred forty-two".