21897582442 has 4 divisors (see below), whose sum is σ = 32846373666. Its totient is φ = 10948791220.

The previous prime is 21897582439. The next prime is 21897582491. The reversal of 21897582442 is 24428579812.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 18605232801 + 3292349641 = 136401^2 + 57379^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21897582442.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5474395609 + ... + 5474395612.

Almost surely, 2^21897582442 is an apocalyptic number.

21897582442 is a deficient number, since it is larger than the sum of its proper divisors (10948791224).

21897582442 is a wasteful number, since it uses less digits than its factorization.

21897582442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10948791223.

The product of its digits is 2580480, while the sum is 52.

The spelling of 21897582442 in words is "twenty-one billion, eight hundred ninety-seven million, five hundred eighty-two thousand, four hundred forty-two".