21807351987456 has 216 divisors, whose sum is σ = 67563595041600. Its totient is φ = 6226203303936.

The previous prime is 21807351987437. The next prime is 21807351987529. The reversal of 21807351987456 is 65478915370812.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 52440060 + ... + 52854276.

It is a 1-persistent number, because it is pandigital, but 2⋅21807351987456 = 43614703974912 is not.

Almost surely, 2^{21807351987456} 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 21807351987456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33781797520800).

21807351987456 is an abundant number, since it is smaller than the sum of its proper divisors (45756243054144).

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

21807351987456 is a wasteful number, since it uses less digits than its factorization.

21807351987456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 415649 (or 415628 counting only the distinct ones).

The product of its (nonzero) digits is 101606400, while the sum is 66.

The spelling of 21807351987456 in words is "twenty-one trillion, eight hundred seven billion, three hundred fifty-one million, nine hundred eighty-seven thousand, four hundred fifty-six".