21235452672 has 144 divisors (see below), whose sum is σ = 64922280192. Its totient is φ = 6036172800.

The previous prime is 21235452659. The next prime is 21235452677. The reversal of 21235452672 is 27625453212.

It is a self number, because there is not a number n which added to its sum of digits gives 21235452672.

It is not an unprimeable number, because it can be changed into a prime (21235452677) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1049047 + ... + 1069097.

It is an arithmetic number, because the mean of its divisors is an integer number (450849168).

Almost surely, 2^21235452672 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 21235452672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32461140096).

21235452672 is an abundant number, since it is smaller than the sum of its proper divisors (43686827520).

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

21235452672 is a wasteful number, since it uses less digits than its factorization.

21235452672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20274 (or 20260 counting only the distinct ones).

The product of its digits is 201600, while the sum is 39.

The spelling of 21235452672 in words is "twenty-one billion, two hundred thirty-five million, four hundred fifty-two thousand, six hundred seventy-two".