21361266260 has 24 divisors (see below), whose sum is σ = 44861479656. Its totient is φ = 8543969280.

The previous prime is 21361266259. The next prime is 21361266263. The reversal of 21361266260 is 6266216312.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1614271684 + 19746994576 = 40178^2 + 140524^2 .

It is a super-2 number, since 2×21361266260² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21361266260.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21361266263) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 496820 + ... + 538100.

It is an arithmetic number, because the mean of its divisors is an integer number (1869228319).

Almost surely, 2^21361266260 is an apocalyptic number.

21361266260 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21361266260 is an abundant number, since it is smaller than the sum of its proper divisors (23500213396).

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

21361266260 is a wasteful number, since it uses less digits than its factorization.

21361266260 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67163 (or 67161 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 35.

The spelling of 21361266260 in words is "twenty-one billion, three hundred sixty-one million, two hundred sixty-six thousand, two hundred sixty".