661728453 has 8 divisors (see below), whose sum is σ = 887234400. Its totient is φ = 438687408.

The previous prime is 661728443. The next prime is 661728491. The reversal of 661728453 is 354827166.

661728453 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 661728453 - 2⁵ = 661728421 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661728413) 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, 615598 + ... + 616671.

It is an arithmetic number, because the mean of its divisors is an integer number (110904300).

Almost surely, 2^661728453 is an apocalyptic number.

It is an amenable number.

661728453 is a deficient number, since it is larger than the sum of its proper divisors (225505947).

661728453 is a wasteful number, since it uses less digits than its factorization.

661728453 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1232451.

The product of its digits is 241920, while the sum is 42.

The square root of 661728453 is about 25724.0831323490. The cubic root of 661728453 is about 871.4181534427.

The spelling of 661728453 in words is "six hundred sixty-one million, seven hundred twenty-eight thousand, four hundred fifty-three".