261564213601123 has 2 divisors, whose sum is σ = 261564213601124. Its totient is φ = 261564213601122.

The previous prime is 261564213601099. The next prime is 261564213601181. The reversal of 261564213601123 is 321106312465162.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 261564213601123 - 2⁹ = 261564213600611 is a prime.

It is a super-2 number, since 2×261564213601123² (a number of 30 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 261564213601123.

It is not a weakly prime, because it can be changed into another prime (261564213301123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130782106800561 + 130782106800562.

It is an arithmetic number, because the mean of its divisors is an integer number (130782106800562).

Almost surely, 2^{261564213601123} is an apocalyptic number.

261564213601123 is a deficient number, since it is larger than the sum of its proper divisors (1).

261564213601123 is an equidigital number, since it uses as much as digits as its factorization.

261564213601123 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 311040, while the sum is 43.

The spelling of 261564213601123 in words is "two hundred sixty-one trillion, five hundred sixty-four billion, two hundred thirteen million, six hundred one thousand, one hundred twenty-three".