21321433998 has 72 divisors (see below), whose sum is σ = 47930259000. Its totient is φ = 6849759168.

The previous prime is 21321433981. The next prime is 21321433999. The reversal of 21321433998 is 89933412312.

21321433998 is a `hidden beast` number, since 2 + 13 + 214 + 339 + 98 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21321433999) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 12548553 + ... + 12550251.

Almost surely, 2^21321433998 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21321433998, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23965129500).

21321433998 is an abundant number, since it is smaller than the sum of its proper divisors (26608825002).

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

21321433998 is a wasteful number, since it uses less digits than its factorization.

21321433998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2594 (or 2562 counting only the distinct ones).

The product of its digits is 279936, while the sum is 45.

The spelling of 21321433998 in words is "twenty-one billion, three hundred twenty-one million, four hundred thirty-three thousand, nine hundred ninety-eight".