261954163 has 2 divisors, whose sum is σ = 261954164. Its totient is φ = 261954162.

The previous prime is 261954131. The next prime is 261954169. The reversal of 261954163 is 361459162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261954163 - 2⁵ = 261954131 is a prime.

It is not a weakly prime, because it can be changed into another prime (261954169) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130977081 + 130977082.

It is an arithmetic number, because the mean of its divisors is an integer number (130977082).

Almost surely, 2^261954163 is an apocalyptic number.

261954163 is a deficient number, since it is larger than the sum of its proper divisors (1).

261954163 is an equidigital number, since it uses as much as digits as its factorization.

261954163 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 38880, while the sum is 37.

The square root of 261954163 is about 16184.9980846462. The cubic root of 261954163 is about 639.8454729466.

The spelling of 261954163 in words is "two hundred sixty-one million, nine hundred fifty-four thousand, one hundred sixty-three".