661276243 has 4 divisors (see below), whose sum is σ = 690027408. Its totient is φ = 632525080.

The previous prime is 661276223. The next prime is 661276261. The reversal of 661276243 is 342672166.

661276243 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 661276243 - 2⁵ = 661276211 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661276223) 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, 14375548 + ... + 14375593.

It is an arithmetic number, because the mean of its divisors is an integer number (172506852).

Almost surely, 2^661276243 is an apocalyptic number.

661276243 is a deficient number, since it is larger than the sum of its proper divisors (28751165).

661276243 is a wasteful number, since it uses less digits than its factorization.

661276243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28751164.

The product of its digits is 72576, while the sum is 37.

The square root of 661276243 is about 25715.2920068974. The cubic root of 661276243 is about 871.2196058360.

The spelling of 661276243 in words is "six hundred sixty-one million, two hundred seventy-six thousand, two hundred forty-three".