261944785 has 4 divisors (see below), whose sum is σ = 314333748. Its totient is φ = 209555824.

The previous prime is 261944779. The next prime is 261944821. The reversal of 261944785 is 587449162.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 587449162 = 2 ⋅293724581.

It can be written as a sum of positive squares in 2 ways, for example, as 62457409 + 199487376 = 7903^2 + 14124^2 .

It is a cyclic number.

It is not a de Polignac number, because 261944785 - 2⁹ = 261944273 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26194474 + ... + 26194483.

It is an arithmetic number, because the mean of its divisors is an integer number (78583437).

Almost surely, 2^261944785 is an apocalyptic number.

It is an amenable number.

261944785 is a deficient number, since it is larger than the sum of its proper divisors (52388963).

261944785 is an equidigital number, since it uses as much as digits as its factorization.

261944785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52388962.

The product of its digits is 483840, while the sum is 46.

The square root of 261944785 is about 16184.7083693220. The cubic root of 261944785 is about 639.8378373328.

The spelling of 261944785 in words is "two hundred sixty-one million, nine hundred forty-four thousand, seven hundred eighty-five".