669814681 has 4 divisors (see below), whose sum is σ = 669972772. Its totient is φ = 669656592.

The previous prime is 669814643. The next prime is 669814687. The reversal of 669814681 is 186418966.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 580039056 + 89775625 = 24084^2 + 9475^2 .

It is a cyclic number.

It is not a de Polignac number, because 669814681 - 2⁷ = 669814553 is a prime.

It is a super-2 number, since 2×669814681² = 897303413766263522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (669814687) 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, 72510 + ... + 81223.

It is an arithmetic number, because the mean of its divisors is an integer number (167493193).

Almost surely, 2^669814681 is an apocalyptic number.

It is an amenable number.

669814681 is a deficient number, since it is larger than the sum of its proper divisors (158091).

669814681 is a wasteful number, since it uses less digits than its factorization.

669814681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158090.

The product of its digits is 497664, while the sum is 49.

The square root of 669814681 is about 25880.7782147292. The cubic root of 669814681 is about 874.9533280140.

The spelling of 669814681 in words is "six hundred sixty-nine million, eight hundred fourteen thousand, six hundred eighty-one".