21339942 has 32 divisors (see below), whose sum is σ = 46321632. Its totient is φ = 6514944.

The previous prime is 21339931. The next prime is 21339943. The reversal of 21339942 is 24993312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21339943) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9688 + ... + 11684.

It is an arithmetic number, because the mean of its divisors is an integer number (1447551).

Almost surely, 2^21339942 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21339942, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23160816).

21339942 is an abundant number, since it is smaller than the sum of its proper divisors (24981690).

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

21339942 is a wasteful number, since it uses less digits than its factorization.

21339942 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2152.

The product of its digits is 11664, while the sum is 33.

The square root of 21339942 is about 4619.5175072728. The cubic root of 21339942 is about 277.3731454932.

The spelling of 21339942 in words is "twenty-one million, three hundred thirty-nine thousand, nine hundred forty-two".