261612166213 has 4 divisors (see below), whose sum is σ = 261653222668. Its totient is φ = 261571109760.

The previous prime is 261612166117. The next prime is 261612166273. The reversal of 261612166213 is 312661216162.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 156355394724 + 105256771489 = 395418^2 + 324433^2 .

It is a cyclic number.

It is not a de Polignac number, because 261612166213 - 2¹³ = 261612158021 is a prime.

It is a super-2 number, since 2×261612166213² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261612166273) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20518668 + ... + 20531413.

It is an arithmetic number, because the mean of its divisors is an integer number (65413305667).

Almost surely, 2^261612166213 is an apocalyptic number.

It is an amenable number.

261612166213 is a deficient number, since it is larger than the sum of its proper divisors (41056455).

261612166213 is an equidigital number, since it uses as much as digits as its factorization.

261612166213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41056454.

The product of its digits is 31104, while the sum is 37.

The spelling of 261612166213 in words is "two hundred sixty-one billion, six hundred twelve million, one hundred sixty-six thousand, two hundred thirteen".