21535248720 has 40 divisors (see below), whose sum is σ = 66759271776. Its totient is φ = 5742732928.

The previous prime is 21535248667. The next prime is 21535248731. The reversal of 21535248720 is 2784253512.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44864862 + ... + 44865341.

Almost surely, 2^21535248720 is an apocalyptic number.

21535248720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21535248720 is an abundant number, since it is smaller than the sum of its proper divisors (45224023056).

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

21535248720 is a wasteful number, since it uses less digits than its factorization.

21535248720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89730219 (or 89730213 counting only the distinct ones).

The product of its (nonzero) digits is 134400, while the sum is 39.

The spelling of 21535248720 in words is "twenty-one billion, five hundred thirty-five million, two hundred forty-eight thousand, seven hundred twenty".