21785574244 has 18 divisors (see below), whose sum is σ = 44349205110. Its totient is φ = 9336674592.

The previous prime is 21785574233. The next prime is 21785574269. The reversal of 21785574244 is 44247558712.

It can be written as a sum of positive squares in only one way, i.e., 15455462400 + 6330111844 = 124320^2 + 79562^2 .

It is a super-2 number, since 2×21785574244² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 55575249 + ... + 55575640.

Almost surely, 2^21785574244 is an apocalyptic number.

It is an amenable number.

21785574244 is an abundant number, since it is smaller than the sum of its proper divisors (22563630866).

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

21785574244 is a wasteful number, since it uses less digits than its factorization.

21785574244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111150907 (or 111150898 counting only the distinct ones).

The product of its digits is 2508800, while the sum is 49.

The spelling of 21785574244 in words is "twenty-one billion, seven hundred eighty-five million, five hundred seventy-four thousand, two hundred forty-four".