21535821832 has 24 divisors (see below), whose sum is σ = 46972265310. Its totient is φ = 9229637760.

The previous prime is 21535821793. The next prime is 21535821893. The reversal of 21535821832 is 23812853512.

It can be written as a sum of positive squares in only one way, i.e., 21530866756 + 4955076 = 146734^2 + 2226^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 27468769 + ... + 27469552.

Almost surely, 2^21535821832 is an apocalyptic number.

It is an amenable number.

21535821832 is an abundant number, since it is smaller than the sum of its proper divisors (25436443478).

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

21535821832 is a wasteful number, since it uses less digits than its factorization.

21535821832 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54938341 (or 54938330 counting only the distinct ones).

The product of its digits is 115200, while the sum is 40.

The spelling of 21535821832 in words is "twenty-one billion, five hundred thirty-five million, eight hundred twenty-one thousand, eight hundred thirty-two".