21642342 has 16 divisors (see below), whose sum is σ = 44340912. Its totient is φ = 7038080.

The previous prime is 21642337. The next prime is 21642359. The reversal of 21642342 is 24324612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 43743 + ... + 44234.

It is an arithmetic number, because the mean of its divisors is an integer number (2771307).

Almost surely, 2^21642342 is an apocalyptic number.

21642342 is an abundant number, since it is smaller than the sum of its proper divisors (22698570).

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

21642342 is a wasteful number, since it uses less digits than its factorization.

21642342 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88023.

The product of its digits is 2304, while the sum is 24.

The square root of 21642342 is about 4652.1330591461. The cubic root of 21642342 is about 278.6771873071.

Adding to 21642342 its reverse (24324612), we get a palindrome (45966954).

The spelling of 21642342 in words is "twenty-one million, six hundred forty-two thousand, three hundred forty-two".