261491329 has 8 divisors (see below), whose sum is σ = 289171872. Its totient is φ = 234462240.

The previous prime is 261491311. The next prime is 261491333. The reversal of 261491329 is 923194162.

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 261491329 - 2¹¹ = 261489281 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261491309) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 162019 + ... + 163624.

It is an arithmetic number, because the mean of its divisors is an integer number (36146484).

Almost surely, 2^261491329 is an apocalyptic number.

It is an amenable number.

261491329 is a deficient number, since it is larger than the sum of its proper divisors (27680543).

261491329 is a wasteful number, since it uses less digits than its factorization.

261491329 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 325727.

The product of its digits is 23328, while the sum is 37.

The square root of 261491329 is about 16170.6935225426. The cubic root of 261491329 is about 639.4684135650.

The spelling of 261491329 in words is "two hundred sixty-one million, four hundred ninety-one thousand, three hundred twenty-nine".