261645487 has 8 divisors (see below), whose sum is σ = 285973632. Its totient is φ = 238310400.

The previous prime is 261645479. The next prime is 261645491. The reversal of 261645487 is 784546162.

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 261645487 - 2³ = 261645479 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261645407) 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, 247714 + ... + 248767.

It is an arithmetic number, because the mean of its divisors is an integer number (35746704).

Almost surely, 2^261645487 is an apocalyptic number.

261645487 is a deficient number, since it is larger than the sum of its proper divisors (24328145).

261645487 is a wasteful number, since it uses less digits than its factorization.

261645487 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 496529.

The product of its digits is 322560, while the sum is 43.

The square root of 261645487 is about 16175.4594061498. The cubic root of 261645487 is about 639.5940516457.

The spelling of 261645487 in words is "two hundred sixty-one million, six hundred forty-five thousand, four hundred eighty-seven".