261012385509 has 8 divisors (see below), whose sum is σ = 348024405792. Its totient is φ = 174004311120.

The previous prime is 261012385493. The next prime is 261012385553. The reversal of 261012385509 is 905583210162.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 261012385509 - 2⁴ = 261012385493 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261012305509) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 828514 + ... + 1099299.

It is an arithmetic number, because the mean of its divisors is an integer number (43503050724).

Almost surely, 2^261012385509 is an apocalyptic number.

It is an amenable number.

261012385509 is a deficient number, since it is larger than the sum of its proper divisors (87012020283).

261012385509 is a wasteful number, since it uses less digits than its factorization.

261012385509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1972947.

The product of its (nonzero) digits is 129600, while the sum is 42.

The spelling of 261012385509 in words is "two hundred sixty-one billion, twelve million, three hundred eighty-five thousand, five hundred nine".