261987429 has 32 divisors (see below), whose sum is σ = 387265536. Its totient is φ = 156225920.

The previous prime is 261987413. The next prime is 261987461. The reversal of 261987429 is 924789162.

It is a cyclic number.

It is not a de Polignac number, because 261987429 - 2⁴ = 261987413 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261987469) 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 31 ways as a sum of consecutive naturals, for example, 754834 + ... + 755180.

It is an arithmetic number, because the mean of its divisors is an integer number (12102048).

Almost surely, 2^261987429 is an apocalyptic number.

It is an amenable number.

261987429 is a deficient number, since it is larger than the sum of its proper divisors (125278107).

261987429 is a wasteful number, since it uses less digits than its factorization.

261987429 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 665.

The product of its digits is 435456, while the sum is 48.

The square root of 261987429 is about 16186.0257320937. The cubic root of 261987429 is about 639.8725568179.

The spelling of 261987429 in words is "two hundred sixty-one million, nine hundred eighty-seven thousand, four hundred twenty-nine".