261612243645 has 64 divisors (see below), whose sum is σ = 447518469120. Its totient is φ = 130117612032.

The previous prime is 261612243593. The next prime is 261612243649. The reversal of 261612243645 is 546342216162.

It is a happy number.

It is not a de Polignac number, because 261612243645 - 2¹⁹ = 261611719357 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 261612243597 and 261612243606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261612243649) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 10868994 + ... + 10893036.

It is an arithmetic number, because the mean of its divisors is an integer number (6992476080).

Almost surely, 2^261612243645 is an apocalyptic number.

It is an amenable number.

261612243645 is a deficient number, since it is larger than the sum of its proper divisors (185906225475).

261612243645 is a wasteful number, since it uses less digits than its factorization.

261612243645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24666.

The product of its digits is 414720, while the sum is 42.

The spelling of 261612243645 in words is "two hundred sixty-one billion, six hundred twelve million, two hundred forty-three thousand, six hundred forty-five".