21243087760 has 40 divisors (see below), whose sum is σ = 49413946680. Its totient is φ = 8493146112.

The previous prime is 21243087727. The next prime is 21243087787. The reversal of 21243087760 is 6778034212.

It can be written as a sum of positive squares in 4 ways, for example, as 9935104 + 21233152656 = 3152^2 + 145716^2 .

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

It is a Harshad number since it is a multiple of its sum of digits (40).

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, 106206 + ... + 231874.

It is an arithmetic number, because the mean of its divisors is an integer number (1235348667).

Almost surely, 2^21243087760 is an apocalyptic number.

21243087760 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21243087760 is an abundant number, since it is smaller than the sum of its proper divisors (28170858920).

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

21243087760 is a wasteful number, since it uses less digits than its factorization.

21243087760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127795 (or 127789 counting only the distinct ones).

The product of its (nonzero) digits is 112896, while the sum is 40.

The spelling of 21243087760 in words is "twenty-one billion, two hundred forty-three million, eighty-seven thousand, seven hundred sixty".