261779461 has 4 divisors (see below), whose sum is σ = 262903212. Its totient is φ = 260655712.

The previous prime is 261779437. The next prime is 261779503. The reversal of 261779461 is 164977162.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 94206436 + 167573025 = 9706^2 + 12945^2 .

It is a cyclic number.

It is not a de Polignac number, because 261779461 - 2²³ = 253390853 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261779411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 561526 + ... + 561991.

It is an arithmetic number, because the mean of its divisors is an integer number (65725803).

Almost surely, 2^261779461 is an apocalyptic number.

It is an amenable number.

261779461 is a deficient number, since it is larger than the sum of its proper divisors (1123751).

261779461 is a wasteful number, since it uses less digits than its factorization.

261779461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1123750.

The product of its digits is 127008, while the sum is 43.

The square root of 261779461 is about 16179.6001495711. The cubic root of 261779461 is about 639.7031997824.

The spelling of 261779461 in words is "two hundred sixty-one million, seven hundred seventy-nine thousand, four hundred sixty-one".