261817943 has 2 divisors, whose sum is σ = 261817944. Its totient is φ = 261817942.

The previous prime is 261817879. The next prime is 261817951. The reversal of 261817943 is 349718162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261817943 - 2⁶ = 261817879 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261817943.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261817973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130908971 + 130908972.

It is an arithmetic number, because the mean of its divisors is an integer number (130908972).

Almost surely, 2^261817943 is an apocalyptic number.

261817943 is a deficient number, since it is larger than the sum of its proper divisors (1).

261817943 is an equidigital number, since it uses as much as digits as its factorization.

261817943 is an evil number, because the sum of its binary digits is even.

The product of its digits is 72576, while the sum is 41.

The square root of 261817943 is about 16180.7893194368. The cubic root of 261817943 is about 639.7345440449.

The spelling of 261817943 in words is "two hundred sixty-one million, eight hundred seventeen thousand, nine hundred forty-three".