21493477844 has 12 divisors (see below), whose sum is σ = 39593248800. Its totient is φ = 10181121048.

The previous prime is 21493477823. The next prime is 21493477849. The reversal of 21493477844 is 44877439412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21493477849) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 141404384 + ... + 141404535.

It is an arithmetic number, because the mean of its divisors is an integer number (3299437400).

Almost surely, 2^21493477844 is an apocalyptic number.

It is an amenable number.

21493477844 is a deficient number, since it is larger than the sum of its proper divisors (18099770956).

21493477844 is a wasteful number, since it uses less digits than its factorization.

21493477844 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 282808942 (or 282808940 counting only the distinct ones).

The product of its digits is 5419008, while the sum is 53.

The spelling of 21493477844 in words is "twenty-one billion, four hundred ninety-three million, four hundred seventy-seven thousand, eight hundred forty-four".