665781063 has 4 divisors (see below), whose sum is σ = 887708088. Its totient is φ = 443854040.

The previous prime is 665781041. The next prime is 665781091. The reversal of 665781063 is 360187566.

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 665781063 - 2⁵ = 665781031 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665781163) 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, 110963508 + ... + 110963513.

It is an arithmetic number, because the mean of its divisors is an integer number (221927022).

Almost surely, 2^665781063 is an apocalyptic number.

665781063 is a deficient number, since it is larger than the sum of its proper divisors (221927025).

665781063 is a wasteful number, since it uses less digits than its factorization.

665781063 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221927024.

The product of its (nonzero) digits is 181440, while the sum is 42.

The square root of 665781063 is about 25802.7336342489. The cubic root of 665781063 is about 873.1934702925.

The spelling of 665781063 in words is "six hundred sixty-five million, seven hundred eighty-one thousand, sixty-three".