261154901799 has 24 divisors (see below), whose sum is σ = 435723689232. Its totient is φ = 148965361920.

The previous prime is 261154901779. The next prime is 261154901869. The reversal of 261154901799 is 997109451162.

It is a happy number.

261154901799 is a `hidden beast` number, since 2 + 6 + 1 + 1 + 549 + 0 + 1 + 7 + 99 = 666.

It is not a de Polignac number, because 261154901799 - 2¹¹ = 261154899751 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261154901729) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 77584444 + ... + 77587809.

It is an arithmetic number, because the mean of its divisors is an integer number (18155153718).

Almost surely, 2^261154901799 is an apocalyptic number.

261154901799 is a deficient number, since it is larger than the sum of its proper divisors (174568787433).

261154901799 is a wasteful number, since it uses less digits than its factorization.

261154901799 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155172287 (or 155172284 counting only the distinct ones).

The product of its (nonzero) digits is 1224720, while the sum is 54.

The spelling of 261154901799 in words is "two hundred sixty-one billion, one hundred fifty-four million, nine hundred one thousand, seven hundred ninety-nine".