261129771 has 48 divisors (see below), whose sum is σ = 464609280. Its totient is φ = 144380880.

The previous prime is 261129689. The next prime is 261129773. The reversal of 261129771 is 177921162.

It is a happy number.

It is not a de Polignac number, because 261129771 - 2⁷ = 261129643 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (261129773) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 37830 + ... + 44196.

It is an arithmetic number, because the mean of its divisors is an integer number (9679360).

Almost surely, 2^261129771 is an apocalyptic number.

261129771 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

261129771 is a deficient number, since it is larger than the sum of its proper divisors (203479509).

261129771 is a wasteful number, since it uses less digits than its factorization.

261129771 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6421 (or 6408 counting only the distinct ones).

The product of its digits is 10584, while the sum is 36.

The square root of 261129771 is about 16159.5102339149. The cubic root of 261129771 is about 639.1735515721.

The spelling of 261129771 in words is "two hundred sixty-one million, one hundred twenty-nine thousand, seven hundred seventy-one".