661153243 has 4 divisors (see below), whose sum is σ = 661411008. Its totient is φ = 660895480.

The previous prime is 661153153. The next prime is 661153267. The reversal of 661153243 is 342351166.

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 661153243 - 2⁹ = 661152731 is a prime.

It is a super-2 number, since 2×661153243² = 874247221458834098, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (601153243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 124996 + ... + 130177.

It is an arithmetic number, because the mean of its divisors is an integer number (165352752).

Almost surely, 2^661153243 is an apocalyptic number.

661153243 is a deficient number, since it is larger than the sum of its proper divisors (257765).

661153243 is a wasteful number, since it uses less digits than its factorization.

661153243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 257764.

The product of its digits is 12960, while the sum is 31.

The square root of 661153243 is about 25712.9003226007. The cubic root of 661153243 is about 871.1655857209.

The spelling of 661153243 in words is "six hundred sixty-one million, one hundred fifty-three thousand, two hundred forty-three".