261988018031 has 2 divisors, whose sum is σ = 261988018032. Its totient is φ = 261988018030.

The previous prime is 261988017989. The next prime is 261988018067. The reversal of 261988018031 is 130810889162.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261988018031 is a prime.

It is a super-2 number, since 2×261988018031² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261988008031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130994009015 + 130994009016.

It is an arithmetic number, because the mean of its divisors is an integer number (130994009016).

Almost surely, 2^261988018031 is an apocalyptic number.

261988018031 is a deficient number, since it is larger than the sum of its proper divisors (1).

261988018031 is an equidigital number, since it uses as much as digits as its factorization.

261988018031 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 165888, while the sum is 47.

The spelling of 261988018031 in words is "two hundred sixty-one billion, nine hundred eighty-eight million, eighteen thousand, thirty-one".