21539196252 has 144 divisors (see below), whose sum is σ = 65796290560. Its totient is φ = 5803726464.

The previous prime is 21539196227. The next prime is 21539196277. The reversal of 21539196252 is 25269193512.

21539196252 is a `hidden beast` number, since 2 + 1 + 5 + 3 + 9 + 19 + 625 + 2 = 666.

It is an interprime number because it is at equal distance from previous prime (21539196227) and next prime (21539196277).

It is a junction number, because it is equal to n+sod(n) for n = 21539196198 and 21539196207.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1057638 + ... + 1077810.

Almost surely, 2^21539196252 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21539196252, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32898145280).

21539196252 is an abundant number, since it is smaller than the sum of its proper divisors (44257094308).

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

21539196252 is a wasteful number, since it uses less digits than its factorization.

21539196252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20432 (or 20427 counting only the distinct ones).

The product of its digits is 291600, while the sum is 45.

The spelling of 21539196252 in words is "twenty-one billion, five hundred thirty-nine million, one hundred ninety-six thousand, two hundred fifty-two".