21564250242 has 32 divisors (see below), whose sum is σ = 43605706752. Its totient is φ = 7108907904.

The previous prime is 21564250199. The next prime is 21564250289. The reversal of 21564250242 is 24205246512.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 196918 + ... + 286190.

It is an arithmetic number, because the mean of its divisors is an integer number (1362678336).

Almost surely, 2^21564250242 is an apocalyptic number.

21564250242 is an abundant number, since it is smaller than the sum of its proper divisors (22041456510).

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

21564250242 is a wasteful number, since it uses less digits than its factorization.

21564250242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89722.

The product of its (nonzero) digits is 38400, while the sum is 33.

Adding to 21564250242 its reverse (24205246512), we get a palindrome (45769496754).

The spelling of 21564250242 in words is "twenty-one billion, five hundred sixty-four million, two hundred fifty thousand, two hundred forty-two".