261890177201 has 2 divisors, whose sum is σ = 261890177202. Its totient is φ = 261890177200.

The previous prime is 261890177123. The next prime is 261890177261. The reversal of 261890177201 is 102771098162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 244850790976 + 17039386225 = 494824^2 + 130535^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261890177201 is a prime.

It is not a weakly prime, because it can be changed into another prime (261890177261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130945088600 + 130945088601.

It is an arithmetic number, because the mean of its divisors is an integer number (130945088601).

Almost surely, 2^261890177201 is an apocalyptic number.

It is an amenable number.

261890177201 is a deficient number, since it is larger than the sum of its proper divisors (1).

261890177201 is an equidigital number, since it uses as much as digits as its factorization.

261890177201 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 84672, while the sum is 44.

The spelling of 261890177201 in words is "two hundred sixty-one billion, eight hundred ninety million, one hundred seventy-seven thousand, two hundred one".