21555833012 has 24 divisors (see below), whose sum is σ = 44502366720. Its totient is φ = 8940206880.

The previous prime is 21555832999. The next prime is 21555833027. The reversal of 21555833012 is 21033855512.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12416087 + ... + 12417822.

It is an arithmetic number, because the mean of its divisors is an integer number (1854265280).

Almost surely, 2^21555833012 is an apocalyptic number.

It is an amenable number.

21555833012 is an abundant number, since it is smaller than the sum of its proper divisors (22946533708).

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

21555833012 is a wasteful number, since it uses less digits than its factorization.

21555833012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24833951 (or 24833949 counting only the distinct ones).

The product of its (nonzero) digits is 36000, while the sum is 35.

The spelling of 21555833012 in words is "twenty-one billion, five hundred fifty-five million, eight hundred thirty-three thousand, twelve".