21342642 has 16 divisors (see below), whose sum is σ = 42969792. Its totient is φ = 7066800.

The previous prime is 21342641. The next prime is 21342677. The reversal of 21342642 is 24624312.

It is not an unprimeable number, because it can be changed into a prime (21342641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10873 + ... + 12684.

It is an arithmetic number, because the mean of its divisors is an integer number (2685612).

Almost surely, 2^21342642 is an apocalyptic number.

21342642 is an abundant number, since it is smaller than the sum of its proper divisors (21627150).

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

21342642 is a wasteful number, since it uses less digits than its factorization.

21342642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23713.

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

The square root of 21342642 is about 4619.8097363420. The cubic root of 21342642 is about 277.3848430556.

Adding to 21342642 its reverse (24624312), we get a palindrome (45966954).

The spelling of 21342642 in words is "twenty-one million, three hundred forty-two thousand, six hundred forty-two".