261213765 has 16 divisors (see below), whose sum is σ = 419071488. Its totient is φ = 138937536.

The previous prime is 261213751. The next prime is 261213769. The reversal of 261213765 is 567312162.

It is not a de Polignac number, because 261213765 - 2⁴ = 261213749 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261213769) 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, 17749 + ... + 28938.

It is an arithmetic number, because the mean of its divisors is an integer number (26191968).

Almost surely, 2^261213765 is an apocalyptic number.

It is an amenable number.

261213765 is a deficient number, since it is larger than the sum of its proper divisors (157857723).

261213765 is a wasteful number, since it uses less digits than its factorization.

261213765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47068.

The product of its digits is 15120, while the sum is 33.

The square root of 261213765 is about 16162.1089279834. The cubic root of 261213765 is about 639.2420755961.

The spelling of 261213765 in words is "two hundred sixty-one million, two hundred thirteen thousand, seven hundred sixty-five".