669600160681 has 3 divisors (see below), whose sum is σ = 669600978973. Its totient is φ = 669599342390.

The previous prime is 669600160667. The next prime is 669600160687. The reversal of 669600160681 is 186061006966.

The square root of 669600160681 is 818291.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 669600160681 - 2²¹ = 669598063529 is a prime.

It is a super-2 number, since 2×669600160681² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (669600160687) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 409146 + ... + 1227436.

Almost surely, 2^669600160681 is an apocalyptic number.

669600160681 is the 818291-st square number.

669600160681 is the 409146-th centered octagonal number.

It is an amenable number.

669600160681 is a deficient number, since it is larger than the sum of its proper divisors (818292).

669600160681 is an frugal number, since it uses more digits than its factorization.

669600160681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1636582 (or 818291 counting only the distinct ones).

The product of its (nonzero) digits is 559872, while the sum is 49.

Multiplying 669600160681 by its sum of digits (49), we get a square (32810407873369 = 5728037²).

The spelling of 669600160681 in words is "six hundred sixty-nine billion, six hundred million, one hundred sixty thousand, six hundred eighty-one".