669571531 has 4 divisors (see below), whose sum is σ = 678047200. Its totient is φ = 661095864.

The previous prime is 669571481. The next prime is 669571543. The reversal of 669571531 is 135175966.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 135175966 = 2 ⋅67587983.

It is a cyclic number.

It is not a de Polignac number, because 669571531 - 2²³ = 661182923 is a prime.

It is a super-2 number, since 2×669571531² = 896652070251367922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (669571031) 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, 4237716 + ... + 4237873.

It is an arithmetic number, because the mean of its divisors is an integer number (169511800).

Almost surely, 2^669571531 is an apocalyptic number.

669571531 is a deficient number, since it is larger than the sum of its proper divisors (8475669).

669571531 is an equidigital number, since it uses as much as digits as its factorization.

669571531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8475668.

The product of its digits is 170100, while the sum is 43.

The square root of 669571531 is about 25876.0802866276. The cubic root of 669571531 is about 874.8474426819.

The spelling of 669571531 in words is "six hundred sixty-nine million, five hundred seventy-one thousand, five hundred thirty-one".