21438742812 has 24 divisors (see below), whose sum is σ = 50770358016. Its totient is φ = 7039586928.

The previous prime is 21438742783. The next prime is 21438742813. The reversal of 21438742812 is 21824783412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21438742813) 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, 13331748 + ... + 13333355.

It is an arithmetic number, because the mean of its divisors is an integer number (2115431584).

Almost surely, 2^21438742812 is an apocalyptic number.

It is an amenable number.

21438742812 is an abundant number, since it is smaller than the sum of its proper divisors (29331615204).

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

21438742812 is a wasteful number, since it uses less digits than its factorization.

21438742812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26665177 (or 26665175 counting only the distinct ones).

The product of its digits is 172032, while the sum is 42.

The spelling of 21438742812 in words is "twenty-one billion, four hundred thirty-eight million, seven hundred forty-two thousand, eight hundred twelve".