666997469 has 4 divisors (see below), whose sum is σ = 667050396. Its totient is φ = 666944544.

The previous prime is 666997459. The next prime is 666997517. The reversal of 666997469 is 964799666.

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 can be written as a sum of positive squares in 2 ways, for example, as 550465444 + 116532025 = 23462^2 + 10795^2 .

It is a cyclic number.

It is not a de Polignac number, because 666997469 - 2¹² = 666993373 is a prime.

It is a super-2 number, since 2×666997469² = 889771247304811922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666997439) 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, 4577 + ... + 36809.

It is an arithmetic number, because the mean of its divisors is an integer number (166762599).

Almost surely, 2^666997469 is an apocalyptic number.

It is an amenable number.

666997469 is a deficient number, since it is larger than the sum of its proper divisors (52927).

666997469 is a wasteful number, since it uses less digits than its factorization.

666997469 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52926.

The product of its digits is 26453952, while the sum is 62.

The square root of 666997469 is about 25826.2941398877. The cubic root of 666997469 is about 873.7249320719.

The spelling of 666997469 in words is "six hundred sixty-six million, nine hundred ninety-seven thousand, four hundred sixty-nine".