661573763 has 4 divisors (see below), whose sum is σ = 661910040. Its totient is φ = 661237488.

The previous prime is 661573721. The next prime is 661573777. The reversal of 661573763 is 367375166.

661573763 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, and also an emirpimes, since its reverse is a distinct semiprime: 367375166 = 2 ⋅183687583.

It is a cyclic number.

It is not a de Polignac number, because 661573763 - 2²⁸ = 393138307 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661573793) 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, 165170 + ... + 169127.

It is an arithmetic number, because the mean of its divisors is an integer number (165477510).

Almost surely, 2^661573763 is an apocalyptic number.

661573763 is a deficient number, since it is larger than the sum of its proper divisors (336277).

661573763 is a wasteful number, since it uses less digits than its factorization.

661573763 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 336276.

The product of its digits is 476280, while the sum is 44.

The square root of 661573763 is about 25721.0762410907. The cubic root of 661573763 is about 871.3502453359.

The spelling of 661573763 in words is "six hundred sixty-one million, five hundred seventy-three thousand, seven hundred sixty-three".