261563945 has 8 divisors (see below), whose sum is σ = 316135680. Its totient is φ = 207745200.

The previous prime is 261563941. The next prime is 261563999. The reversal of 261563945 is 549365162.

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

It is not a de Polignac number, because 261563945 - 2² = 261563941 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261563941) 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, 187481 + ... + 188870.

It is an arithmetic number, because the mean of its divisors is an integer number (39516960).

Almost surely, 2^261563945 is an apocalyptic number.

It is an amenable number.

261563945 is a deficient number, since it is larger than the sum of its proper divisors (54571735).

261563945 is a wasteful number, since it uses less digits than its factorization.

261563945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 376495.

The product of its digits is 194400, while the sum is 41.

The square root of 261563945 is about 16172.9386630878. The cubic root of 261563945 is about 639.5276014302.

The spelling of 261563945 in words is "two hundred sixty-one million, five hundred sixty-three thousand, nine hundred forty-five".