21531513234 has 96 divisors (see below), whose sum is σ = 57033271296. Its totient is φ = 5263591680.

The previous prime is 21531513173. The next prime is 21531513299. The reversal of 21531513234 is 43231513512.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 52887 + ... + 214149.

It is an arithmetic number, because the mean of its divisors is an integer number (594096576).

Almost surely, 2^21531513234 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21531513234, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28516635648).

21531513234 is an abundant number, since it is smaller than the sum of its proper divisors (35501758062).

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

21531513234 is a wasteful number, since it uses less digits than its factorization.

21531513234 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161320 (or 161303 counting only the distinct ones).

The product of its digits is 10800, while the sum is 30.

The spelling of 21531513234 in words is "twenty-one billion, five hundred thirty-one million, five hundred thirteen thousand, two hundred thirty-four".