261943563 has 24 divisors (see below), whose sum is σ = 407208000. Its totient is φ = 149340240.

The previous prime is 261943537. The next prime is 261943567. The reversal of 261943563 is 365349162.

It is not a de Polignac number, because 261943563 - 2⁸ = 261943307 is a prime.

It is a super-2 number, since 2×261943563² = 137228860394269938, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (261943567) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 71568 + ... + 75138.

It is an arithmetic number, because the mean of its divisors is an integer number (16967000).

Almost surely, 2^261943563 is an apocalyptic number.

261943563 is a deficient number, since it is larger than the sum of its proper divisors (145264437).

261943563 is a wasteful number, since it uses less digits than its factorization.

261943563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4087 (or 4080 counting only the distinct ones).

The product of its digits is 116640, while the sum is 39.

The square root of 261943563 is about 16184.6706175937. The cubic root of 261943563 is about 639.8368423610.

The spelling of 261943563 in words is "two hundred sixty-one million, nine hundred forty-three thousand, five hundred sixty-three".