21178661144 has 16 divisors (see below), whose sum is σ = 41799989400. Its totient is φ = 10031997312.

The previous prime is 21178661143. The next prime is 21178661171. The reversal of 21178661144 is 44116687112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21178661143) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 69666497 + ... + 69666800.

Almost surely, 2^21178661144 is an apocalyptic number.

It is an amenable number.

21178661144 is a deficient number, since it is larger than the sum of its proper divisors (20621328256).

21178661144 is a wasteful number, since it uses less digits than its factorization.

21178661144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 139333322 (or 139333318 counting only the distinct ones).

The product of its digits is 64512, while the sum is 41.

The spelling of 21178661144 in words is "twenty-one billion, one hundred seventy-eight million, six hundred sixty-one thousand, one hundred forty-four".