669897761 has 4 divisors (see below), whose sum is σ = 721428372. Its totient is φ = 618367152.

The previous prime is 669897743. The next prime is 669897769. The reversal of 669897761 is 167798966.

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 147501025 + 522396736 = 12145^2 + 22856^2 .

It is not a de Polignac number, because 669897761 - 2²⁶ = 602788897 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 669897761.

It is not an unprimeable number, because it can be changed into a prime (669897769) 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, 25765286 + ... + 25765311.

It is an arithmetic number, because the mean of its divisors is an integer number (180357093).

Almost surely, 2^669897761 is an apocalyptic number.

It is an amenable number.

669897761 is a deficient number, since it is larger than the sum of its proper divisors (51530611).

669897761 is a wasteful number, since it uses less digits than its factorization.

669897761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51530610.

The product of its digits is 6858432, while the sum is 59.

The square root of 669897761 is about 25882.3832171614. The cubic root of 669897761 is about 874.9895012618.

The spelling of 669897761 in words is "six hundred sixty-nine million, eight hundred ninety-seven thousand, seven hundred sixty-one".