21807247680 has 196 divisors, whose sum is σ = 77857979412. Its totient is φ = 5815203840.

The previous prime is 21807247673. The next prime is 21807247687. The reversal of 21807247680 is 8674270812.

21807247680 is a `hidden beast` number, since 21 + 80 + 7 + 2 + 476 + 80 = 666.

It is an interprime number because it is at equal distance from previous prime (21807247673) and next prime (21807247687).

It can be written as a sum of positive squares in 2 ways, for example, as 13655324736 + 8151922944 = 116856^2 + 90288^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21807247687) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 186540 + ... + 280020.

Almost surely, 2^21807247680 is an apocalyptic number.

21807247680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21807247680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38928989706).

21807247680 is an abundant number, since it is smaller than the sum of its proper divisors (56050731732).

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

21807247680 is an frugal number, since it uses more digits than its factorization.

21807247680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93516 (or 93491 counting only the distinct ones).

The product of its (nonzero) digits is 301056, while the sum is 45.

The spelling of 21807247680 in words is "twenty-one billion, eight hundred seven million, two hundred forty-seven thousand, six hundred eighty".