261997635 has 16 divisors (see below), whose sum is σ = 419408640. Its totient is φ = 139661280.

The previous prime is 261997627. The next prime is 261997639. The reversal of 261997635 is 536799162.

It is not a de Polignac number, because 261997635 - 2³ = 261997627 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261997639) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41626 + ... + 47504.

It is an arithmetic number, because the mean of its divisors is an integer number (26213040).

Almost surely, 2^261997635 is an apocalyptic number.

261997635 is a deficient number, since it is larger than the sum of its proper divisors (157411005).

261997635 is a wasteful number, since it uses less digits than its factorization.

261997635 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8858.

The product of its digits is 612360, while the sum is 48.

The square root of 261997635 is about 16186.3410009798. The cubic root of 261997635 is about 639.8808656829.

The spelling of 261997635 in words is "two hundred sixty-one million, nine hundred ninety-seven thousand, six hundred thirty-five".