21502617472 has 96 divisors (see below), whose sum is σ = 51549831000. Its totient is φ = 8897559552.

The previous prime is 21502617431. The next prime is 21502617473. The reversal of 21502617472 is 27471620512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21502617473) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 122779 + ... + 240997.

Almost surely, 2^21502617472 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 21502617472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25774915500).

21502617472 is an abundant number, since it is smaller than the sum of its proper divisors (30047213528).

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

21502617472 is a wasteful number, since it uses less digits than its factorization.

21502617472 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118276 (or 118257 counting only the distinct ones).

The product of its (nonzero) digits is 47040, while the sum is 37.

The spelling of 21502617472 in words is "twenty-one billion, five hundred two million, six hundred seventeen thousand, four hundred seventy-two".