261622565 has 8 divisors (see below), whose sum is σ = 314125440. Its totient is φ = 209179152.

The previous prime is 261622561. The next prime is 261622567. The reversal of 261622565 is 565226162.

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

It is a cyclic number.

It is not a de Polignac number, because 261622565 - 2² = 261622561 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261622561) 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, 4529 + ... + 23318.

It is an arithmetic number, because the mean of its divisors is an integer number (39265680).

Almost surely, 2^261622565 is an apocalyptic number.

It is an amenable number.

261622565 is a deficient number, since it is larger than the sum of its proper divisors (52502875).

261622565 is a wasteful number, since it uses less digits than its factorization.

261622565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29731.

The product of its digits is 43200, while the sum is 35.

The square root of 261622565 is about 16174.7508481584. The cubic root of 261622565 is about 639.5753734422.

The spelling of 261622565 in words is "two hundred sixty-one million, six hundred twenty-two thousand, five hundred sixty-five".