261563397 has 8 divisors (see below), whose sum is σ = 358177056. Its totient is φ = 169662672.

The previous prime is 261563387. The next prime is 261563447. The reversal of 261563397 is 793365162.

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

It is not a de Polignac number, because 261563397 - 2¹⁰ = 261562373 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261563347) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1178103 + ... + 1178324.

It is an arithmetic number, because the mean of its divisors is an integer number (44772132).

Almost surely, 2^261563397 is an apocalyptic number.

It is an amenable number.

261563397 is a deficient number, since it is larger than the sum of its proper divisors (96613659).

261563397 is a wasteful number, since it uses less digits than its factorization.

261563397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2356467.

The product of its digits is 204120, while the sum is 42.

The square root of 261563397 is about 16172.9217211981. The cubic root of 261563397 is about 639.5271548073.

The spelling of 261563397 in words is "two hundred sixty-one million, five hundred sixty-three thousand, three hundred ninety-seven".