261442165415540 has 12 divisors (see below), whose sum is σ = 549028547372676. Its totient is φ = 104576866166208.

The previous prime is 261442165415513. The next prime is 261442165415551. The reversal of 261442165415540 is 45514561244162.

It can be written as a sum of positive squares in 2 ways, for example, as 39982706483344 + 221459458932196 = 6323188^2 + 14881514^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6536054135369 + ... + 6536054135408.

It is an arithmetic number, because the mean of its divisors is an integer number (45752378947723).

Almost surely, 2^{261442165415540} is an apocalyptic number.

261442165415540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261442165415540 is an abundant number, since it is smaller than the sum of its proper divisors (287586381957136).

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

261442165415540 is a wasteful number, since it uses less digits than its factorization.

261442165415540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13072108270786 (or 13072108270784 counting only the distinct ones).

The product of its (nonzero) digits is 4608000, while the sum is 50.

The spelling of 261442165415540 in words is "two hundred sixty-one trillion, four hundred forty-two billion, one hundred sixty-five million, four hundred fifteen thousand, five hundred forty".