661553223 has 8 divisors (see below), whose sum is σ = 882369408. Its totient is φ = 440886264.

The previous prime is 661553203. The next prime is 661553231. The reversal of 661553223 is 322355166.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 661553223 - 2⁶ = 661553159 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661553203) 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, 26515 + ... + 45012.

It is an arithmetic number, because the mean of its divisors is an integer number (110296176).

Almost surely, 2^661553223 is an apocalyptic number.

661553223 is a deficient number, since it is larger than the sum of its proper divisors (220816185).

661553223 is a wasteful number, since it uses less digits than its factorization.

661553223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74613.

The product of its digits is 32400, while the sum is 33.

The square root of 661553223 is about 25720.6769545438. The cubic root of 661553223 is about 871.3412275865.

It can be divided in two parts, 66155 and 3223, that added together give a triangular number (69378 = T₃₇₂).

The spelling of 661553223 in words is "six hundred sixty-one million, five hundred fifty-three thousand, two hundred twenty-three".