261919979903 has 2 divisors, whose sum is σ = 261919979904. Its totient is φ = 261919979902.

The previous prime is 261919979819. The next prime is 261919979921. The reversal of 261919979903 is 309979919162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261919979903 - 2⁸ = 261919979647 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261919979903.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261919979933) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130959989951 + 130959989952.

It is an arithmetic number, because the mean of its divisors is an integer number (130959989952).

Almost surely, 2^261919979903 is an apocalyptic number.

261919979903 is a deficient number, since it is larger than the sum of its proper divisors (1).

261919979903 is an equidigital number, since it uses as much as digits as its factorization.

261919979903 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14880348, while the sum is 65.

The spelling of 261919979903 in words is "two hundred sixty-one billion, nine hundred nineteen million, nine hundred seventy-nine thousand, nine hundred three".