261326521787 has 2 divisors, whose sum is σ = 261326521788. Its totient is φ = 261326521786.

The previous prime is 261326521783. The next prime is 261326521793. The reversal of 261326521787 is 787125623162.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 261326521787 - 2² = 261326521783 is a prime.

It is not a weakly prime, because it can be changed into another prime (261326521783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130663260893 + 130663260894.

It is an arithmetic number, because the mean of its divisors is an integer number (130663260894).

Almost surely, 2^261326521787 is an apocalyptic number.

261326521787 is a deficient number, since it is larger than the sum of its proper divisors (1).

261326521787 is an equidigital number, since it uses as much as digits as its factorization.

261326521787 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1693440, while the sum is 50.

The spelling of 261326521787 in words is "two hundred sixty-one billion, three hundred twenty-six million, five hundred twenty-one thousand, seven hundred eighty-seven".