261969636 has 12 divisors (see below), whose sum is σ = 611262512. Its totient is φ = 87323208.

The previous prime is 261969611. The next prime is 261969637. The reversal of 261969636 is 636969162.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (12).

It is not an unprimeable number, because it can be changed into a prime (261969637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10915390 + ... + 10915413.

Almost surely, 2^261969636 is an apocalyptic number.

It is an amenable number.

261969636 is an abundant number, since it is smaller than the sum of its proper divisors (349292876).

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

261969636 is a wasteful number, since it uses less digits than its factorization.

261969636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21830810 (or 21830808 counting only the distinct ones).

The product of its digits is 629856, while the sum is 48.

The square root of 261969636 is about 16185.4760819693. The cubic root of 261969636 is about 639.8580707410.

The spelling of 261969636 in words is "two hundred sixty-one million, nine hundred sixty-nine thousand, six hundred thirty-six".