261636331324220 has 96 divisors (see below), whose sum is σ = 569798912901120. Its totient is φ = 100807506305280.

The previous prime is 261636331324139. The next prime is 261636331324243. The reversal of 261636331324220 is 22423133636162.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 840326894 + ... + 840638186.

It is an arithmetic number, because the mean of its divisors is an integer number (5935405342720).

Almost surely, 2^{261636331324220} is an apocalyptic number.

261636331324220 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 261636331324220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (284899456450560).

261636331324220 is an abundant number, since it is smaller than the sum of its proper divisors (308162581576900).

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

261636331324220 is a wasteful number, since it uses less digits than its factorization.

261636331324220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 317635 (or 317633 counting only the distinct ones).

The product of its (nonzero) digits is 1119744, while the sum is 44.

The spelling of 261636331324220 in words is "two hundred sixty-one trillion, six hundred thirty-six billion, three hundred thirty-one million, three hundred twenty-four thousand, two hundred twenty".