261656623 has 4 divisors (see below), whose sum is σ = 264102120. Its totient is φ = 259211128.

The previous prime is 261656599. The next prime is 261656663. The reversal of 261656623 is 326656162.

261656623 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 261656623 - 2²¹ = 259559471 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 (261656663) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1222588 + ... + 1222801.

It is an arithmetic number, because the mean of its divisors is an integer number (66025530).

Almost surely, 2^261656623 is an apocalyptic number.

261656623 is a deficient number, since it is larger than the sum of its proper divisors (2445497).

261656623 is a wasteful number, since it uses less digits than its factorization.

261656623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2445496.

The product of its digits is 77760, while the sum is 37.

The square root of 261656623 is about 16175.8036276409. The cubic root of 261656623 is about 639.6031255245.

The spelling of 261656623 in words is "two hundred sixty-one million, six hundred fifty-six thousand, six hundred twenty-three".