261360646641 has 12 divisors (see below), whose sum is σ = 378491429940. Its totient is φ = 173792509920.

The previous prime is 261360646637. The next prime is 261360646661. The reversal of 261360646641 is 146646063162.

261360646641 is a `hidden beast` number, since 26 + 13 + 606 + 4 + 6 + 6 + 4 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 106061600241 + 155299046400 = 325671^2 + 394080^2 .

It is not a de Polignac number, because 261360646641 - 2² = 261360646637 is a prime.

It is a super-2 number, since 2×261360646641² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (261360646601) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 37323070 + ... + 37330071.

It is an arithmetic number, because the mean of its divisors is an integer number (31540952495).

Almost surely, 2^261360646641 is an apocalyptic number.

It is an amenable number.

261360646641 is a deficient number, since it is larger than the sum of its proper divisors (117130783299).

261360646641 is a wasteful number, since it uses less digits than its factorization.

261360646641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74653536 (or 74653533 counting only the distinct ones).

The product of its (nonzero) digits is 746496, while the sum is 45.

The spelling of 261360646641 in words is "two hundred sixty-one billion, three hundred sixty million, six hundred forty-six thousand, six hundred forty-one".