21401840444 has 24 divisors (see below), whose sum is σ = 37582608000. Its totient is φ = 10663999920.

The previous prime is 21401840441. The next prime is 21401840479. The reversal of 21401840444 is 44404810412.

It is a self number, because there is not a number n which added to its sum of digits gives 21401840444.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21401840441) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2115839 + ... + 2125929.

It is an arithmetic number, because the mean of its divisors is an integer number (1565942000).

Almost surely, 2^21401840444 is an apocalyptic number.

It is an amenable number.

21401840444 is a deficient number, since it is larger than the sum of its proper divisors (16180767556).

21401840444 is a wasteful number, since it uses less digits than its factorization.

21401840444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11873 (or 11871 counting only the distinct ones).

The product of its (nonzero) digits is 16384, while the sum is 32.

The spelling of 21401840444 in words is "twenty-one billion, four hundred one million, eight hundred forty thousand, four hundred forty-four".