261126290081 has 4 divisors (see below), whose sum is σ = 261127409664. Its totient is φ = 261125170500.

The previous prime is 261126290077. The next prime is 261126290101. The reversal of 261126290081 is 180092621162.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 261126290081 - 2² = 261126290077 is a prime.

It is a super-2 number, since 2×261126290081² (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 (261126290681) 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, 62945 + ... + 725406.

It is an arithmetic number, because the mean of its divisors is an integer number (65281852416).

Almost surely, 2^261126290081 is an apocalyptic number.

It is an amenable number.

261126290081 is a deficient number, since it is larger than the sum of its proper divisors (1119583).

261126290081 is an equidigital number, since it uses as much as digits as its factorization.

261126290081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1119582.

The product of its (nonzero) digits is 20736, while the sum is 38.

The spelling of 261126290081 in words is "two hundred sixty-one billion, one hundred twenty-six million, two hundred ninety thousand, eighty-one".