261749545379 has 4 divisors (see below), whose sum is σ = 299142337584. Its totient is φ = 224356753176.

The previous prime is 261749545363. The next prime is 261749545429. The reversal of 261749545379 is 973545947162.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 261749545379 - 2⁴ = 261749545363 is a prime.

It is a super-2 number, since 2×261749545379² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261749545979) 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, 18696396092 + ... + 18696396105.

It is an arithmetic number, because the mean of its divisors is an integer number (74785584396).

Almost surely, 2^261749545379 is an apocalyptic number.

261749545379 is a deficient number, since it is larger than the sum of its proper divisors (37392792205).

261749545379 is an equidigital number, since it uses as much as digits as its factorization.

261749545379 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37392792204.

The product of its digits is 57153600, while the sum is 62.

The spelling of 261749545379 in words is "two hundred sixty-one billion, seven hundred forty-nine million, five hundred forty-five thousand, three hundred seventy-nine".