291620261 has 8 divisors (see below), whose sum is σ = 311662080. Its totient is φ = 271899328.

The previous prime is 291620239. The next prime is 291620269. The reversal of 291620261 is 162026192.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 291620261 - 2¹⁸ = 291358117 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (291620269) 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 7 ways as a sum of consecutive naturals, for example, 78341 + ... + 81978.

It is an arithmetic number, because the mean of its divisors is an integer number (38957760).

Almost surely, 2^291620261 is an apocalyptic number.

It is an amenable number.

291620261 is a deficient number, since it is larger than the sum of its proper divisors (20041819).

291620261 is a wasteful number, since it uses less digits than its factorization.

291620261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160443.

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 291620261 is about 17076.8926037497. The cubic root of 291620261 is about 663.1410278692.

The spelling of 291620261 in words is "two hundred ninety-one million, six hundred twenty thousand, two hundred sixty-one".