661044243 has 4 divisors (see below), whose sum is σ = 881392328. Its totient is φ = 440696160.

The previous prime is 661044239. The next prime is 661044259. The reversal of 661044243 is 342440166.

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

It is not a de Polignac number, because 661044243 - 2² = 661044239 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 661044243.

It is not an unprimeable number, because it can be changed into a prime (661049243) 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, 110174038 + ... + 110174043.

It is an arithmetic number, because the mean of its divisors is an integer number (220348082).

Almost surely, 2^661044243 is an apocalyptic number.

661044243 is a deficient number, since it is larger than the sum of its proper divisors (220348085).

661044243 is a wasteful number, since it uses less digits than its factorization.

661044243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220348084.

The product of its (nonzero) digits is 13824, while the sum is 30.

The square root of 661044243 is about 25710.7806765956. The cubic root of 661044243 is about 871.1177086371.

The spelling of 661044243 in words is "six hundred sixty-one million, forty-four thousand, two hundred forty-three".