247661 has 4 divisors (see below), whose sum is σ = 249312. Its totient is φ = 246012.

The previous prime is 247651. The next prime is 247691. The reversal of 247661 is 166742.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 247661 - 2¹⁰ = 246637 is a prime.

It is a super-2 number, since 2×247661² = 122671941842, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 247661.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 247661.

It is not an unprimeable number, because it can be changed into a prime (247601) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 575 + ... + 908.

It is an arithmetic number, because the mean of its divisors is an integer number (62328).

2²⁴⁷⁶⁶¹ is an apocalyptic number.

It is an amenable number.

247661 is a deficient number, since it is larger than the sum of its proper divisors (1651).

247661 is a wasteful number, since it uses less digits than its factorization.

247661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1650.

The product of its digits is 2016, while the sum is 26.

The square root of 247661 is about 497.6555033354. The cubic root of 247661 is about 62.7989728962.

The spelling of 247661 in words is "two hundred forty-seven thousand, six hundred sixty-one".