261981223715 has 16 divisors (see below), whose sum is σ = 314742703968. Its totient is φ = 209341606656.

The previous prime is 261981223661. The next prime is 261981223741. The reversal of 261981223715 is 517322189162.

It is a cyclic number.

It is not a de Polignac number, because 261981223715 - 2³⁴ = 244801354531 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 261981223715.

It is an unprimeable number.

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 in 15 ways as a sum of consecutive naturals, for example, 33356729 + ... + 33364581.

It is an arithmetic number, because the mean of its divisors is an integer number (19671418998).

Almost surely, 2^261981223715 is an apocalyptic number.

261981223715 is a deficient number, since it is larger than the sum of its proper divisors (52761480253).

261981223715 is a wasteful number, since it uses less digits than its factorization.

261981223715 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14758.

The product of its digits is 362880, while the sum is 47.

The spelling of 261981223715 in words is "two hundred sixty-one billion, nine hundred eighty-one million, two hundred twenty-three thousand, seven hundred fifteen".