21188261284 has 12 divisors (see below), whose sum is σ = 37081451484. Its totient is φ = 10593560864.

The previous prime is 21188261267. The next prime is 21188261317. The reversal of 21188261284 is 48216288112.

It can be written as a sum of positive squares in 2 ways, for example, as 11996820900 + 9191440384 = 109530^2 + 95872^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21188261284.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 52459 + ... + 212434.

It is an arithmetic number, because the mean of its divisors is an integer number (3090120957).

Almost surely, 2^21188261284 is an apocalyptic number.

It is an amenable number.

21188261284 is a deficient number, since it is larger than the sum of its proper divisors (15893190200).

21188261284 is a wasteful number, since it uses less digits than its factorization.

21188261284 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 284894 (or 284892 counting only the distinct ones).

The product of its digits is 98304, while the sum is 43.

The spelling of 21188261284 in words is "twenty-one billion, one hundred eighty-eight million, two hundred sixty-one thousand, two hundred eighty-four".