21252642 has 16 divisors (see below), whose sum is σ = 42553632. Its totient is φ = 7076160.

The previous prime is 21252617. The next prime is 21252653. The reversal of 21252642 is 24625212.

It is a happy 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, 6417 + ... + 9147.

It is an arithmetic number, because the mean of its divisors is an integer number (2659602).

Almost surely, 2^21252642 is an apocalyptic number.

21252642 is an abundant number, since it is smaller than the sum of its proper divisors (21300990).

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

21252642 is a wasteful number, since it uses less digits than its factorization.

21252642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4033.

The product of its digits is 1920, while the sum is 24.

The square root of 21252642 is about 4610.0587848747. The cubic root of 21252642 is about 276.9943914029.

Adding to 21252642 its reverse (24625212), we get a palindrome (45877854).

The spelling of 21252642 in words is "twenty-one million, two hundred fifty-two thousand, six hundred forty-two".