21399461844 has 12 divisors (see below), whose sum is σ = 49932077664. Its totient is φ = 7133153944.

The previous prime is 21399461827. The next prime is 21399461861. The reversal of 21399461844 is 44816499312.

It is an interprime number because it is at equal distance from previous prime (21399461827) and next prime (21399461861).

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

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, 891644232 + ... + 891644255.

It is an arithmetic number, because the mean of its divisors is an integer number (4161006472).

Almost surely, 2^21399461844 is an apocalyptic number.

It is an amenable number.

21399461844 is an abundant number, since it is smaller than the sum of its proper divisors (28532615820).

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

21399461844 is a wasteful number, since it uses less digits than its factorization.

21399461844 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1783288494 (or 1783288492 counting only the distinct ones).

The product of its digits is 1492992, while the sum is 51.

The spelling of 21399461844 in words is "twenty-one billion, three hundred ninety-nine million, four hundred sixty-one thousand, eight hundred forty-four".