261878623 has 2 divisors, whose sum is σ = 261878624. Its totient is φ = 261878622.

The previous prime is 261878609. The next prime is 261878629. The reversal of 261878623 is 326878162.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261878623 is a prime.

It is a super-2 number, since 2×261878623² = 137160826368752258, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 261878623.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261878629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130939311 + 130939312.

It is an arithmetic number, because the mean of its divisors is an integer number (130939312).

Almost surely, 2^261878623 is an apocalyptic number.

261878623 is a deficient number, since it is larger than the sum of its proper divisors (1).

261878623 is an equidigital number, since it uses as much as digits as its factorization.

261878623 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 193536, while the sum is 43.

The square root of 261878623 is about 16182.6642738456. The cubic root of 261878623 is about 639.7839627276.

The spelling of 261878623 in words is "two hundred sixty-one million, eight hundred seventy-eight thousand, six hundred twenty-three".