261922238161 has 8 divisors (see below), whose sum is σ = 262637317800. Its totient is φ = 261207373440.

The previous prime is 261922238147. The next prime is 261922238173. The reversal of 261922238161 is 161832229162.

It can be written as a sum of positive squares in 4 ways, for example, as 3801339025 + 258120899136 = 61655^2 + 508056^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 261922238161 - 2⁷ = 261922238033 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261922238101) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2559621 + ... + 2659981.

It is an arithmetic number, because the mean of its divisors is an integer number (32829664725).

Almost surely, 2^261922238161 is an apocalyptic number.

It is an amenable number.

261922238161 is a deficient number, since it is larger than the sum of its proper divisors (715079639).

261922238161 is a wasteful number, since it uses less digits than its factorization.

261922238161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107459.

The product of its digits is 124416, while the sum is 43.

The spelling of 261922238161 in words is "two hundred sixty-one billion, nine hundred twenty-two million, two hundred thirty-eight thousand, one hundred sixty-one".