261897757 has 16 divisors (see below), whose sum is σ = 299230848. Its totient is φ = 226895680.

The previous prime is 261897743. The next prime is 261897761. The reversal of 261897757 is 757798162.

It is not a de Polignac number, because 261897757 - 2²³ = 253509149 is a prime.

It is a super-3 number, since 3×261897757³ (a number of 26 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261897787) 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 in 15 ways as a sum of consecutive naturals, for example, 72363 + ... + 75895.

It is an arithmetic number, because the mean of its divisors is an integer number (18701928).

Almost surely, 2^261897757 is an apocalyptic number.

It is an amenable number.

261897757 is a deficient number, since it is larger than the sum of its proper divisors (37333091).

261897757 is a wasteful number, since it uses less digits than its factorization.

261897757 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3860.

The product of its digits is 1481760, while the sum is 52.

The square root of 261897757 is about 16183.2554512372. The cubic root of 261897757 is about 639.7995441549.

The spelling of 261897757 in words is "two hundred sixty-one million, eight hundred ninety-seven thousand, seven hundred fifty-seven".