669567791 has 8 divisors (see below), whose sum is σ = 695574144. Its totient is φ = 643836960.

The previous prime is 669567779. The next prime is 669567793. The reversal of 669567791 is 197765966.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-669567791 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (669567793) 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, 63920 + ... + 73653.

It is an arithmetic number, because the mean of its divisors is an integer number (86946768).

Almost surely, 2^669567791 is an apocalyptic number.

669567791 is a deficient number, since it is larger than the sum of its proper divisors (26006353).

669567791 is a wasteful number, since it uses less digits than its factorization.

669567791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137761.

The product of its digits is 4286520, while the sum is 56.

The square root of 669567791 is about 25876.0080190125. The cubic root of 669567791 is about 874.8458138116.

It can be divided in two parts, 66956 and 7791, that added together give a palindrome (74747).

The spelling of 669567791 in words is "six hundred sixty-nine million, five hundred sixty-seven thousand, seven hundred ninety-one".