261609189972 has 48 divisors (see below), whose sum is σ = 657753913152. Its totient is φ = 80448975360.

The previous prime is 261609189971. The next prime is 261609189997. The reversal of 261609189972 is 279981906162.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261609189971) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 207429 + ... + 752492.

It is an arithmetic number, because the mean of its divisors is an integer number (13703206524).

Almost surely, 2^261609189972 is an apocalyptic number.

It is an amenable number.

261609189972 is an abundant number, since it is smaller than the sum of its proper divisors (396144723180).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261609189972 is a wasteful number, since it uses less digits than its factorization.

261609189972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 961688 (or 961686 counting only the distinct ones).

The product of its (nonzero) digits is 5878656, while the sum is 60.

The spelling of 261609189972 in words is "two hundred sixty-one billion, six hundred nine million, one hundred eighty-nine thousand, nine hundred seventy-two".