261997637 has 8 divisors (see below), whose sum is σ = 285949440. Its totient is φ = 238068160.

The previous prime is 261997627. The next prime is 261997639. The reversal of 261997637 is 736799162.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 261997637 - 2⁴ = 261997621 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 (261997639) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27533 + ... + 35805.

It is an arithmetic number, because the mean of its divisors is an integer number (35743680).

Almost surely, 2^261997637 is an apocalyptic number.

It is an amenable number.

261997637 is a deficient number, since it is larger than the sum of its proper divisors (23951803).

261997637 is a wasteful number, since it uses less digits than its factorization.

261997637 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11163.

The product of its digits is 857304, while the sum is 50.

The square root of 261997637 is about 16186.3410627603. The cubic root of 261997637 is about 639.8808673111.

The spelling of 261997637 in words is "two hundred sixty-one million, nine hundred ninety-seven thousand, six hundred thirty-seven".