261115136546660 has 384 divisors, whose sum is σ = 630583655546880. Its totient is φ = 89957960294400.

The previous prime is 261115136546657. The next prime is 261115136546683. The reversal of 261115136546660 is 66645631511162.

It is a happy number.

It is a super-2 number, since 2×261115136546660² (a number of 30 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 52889431712 + ... + 52889436648.

It is an arithmetic number, because the mean of its divisors is an integer number (1642144936320).

Almost surely, 2^{261115136546660} is an apocalyptic number.

261115136546660 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 261115136546660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (315291827773440).

261115136546660 is an abundant number, since it is smaller than the sum of its proper divisors (369468519000220).

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

261115136546660 is a wasteful number, since it uses less digits than its factorization.

261115136546660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5747 (or 5745 counting only the distinct ones).

The product of its (nonzero) digits is 4665600, while the sum is 53.

The spelling of 261115136546660 in words is "two hundred sixty-one trillion, one hundred fifteen billion, one hundred thirty-six million, five hundred forty-six thousand, six hundred sixty".