261156623 has 24 divisors (see below), whose sum is σ = 328552560. Its totient is φ = 205752960.

The previous prime is 261156613. The next prime is 261156631. The reversal of 261156623 is 326651162.

It is a de Polignac number, because none of the positive numbers 2^k-261156623 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261156623.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261156613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 178268 + ... + 179726.

It is an arithmetic number, because the mean of its divisors is an integer number (13689690).

Almost surely, 2^261156623 is an apocalyptic number.

261156623 is a deficient number, since it is larger than the sum of its proper divisors (67395937).

261156623 is a wasteful number, since it uses less digits than its factorization.

261156623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1767 (or 1760 counting only the distinct ones).

The product of its digits is 12960, while the sum is 32.

The square root of 261156623 is about 16160.3410545694. The cubic root of 261156623 is about 639.1954595809.

The spelling of 261156623 in words is "two hundred sixty-one million, one hundred fifty-six thousand, six hundred twenty-three".