669506381 has 2 divisors, whose sum is σ = 669506382. Its totient is φ = 669506380.

The previous prime is 669506351. The next prime is 669506413. The reversal of 669506381 is 183605966.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 485497156 + 184009225 = 22034^2 + 13565^2 .

It is a cyclic number.

It is not a de Polignac number, because 669506381 - 2⁶ = 669506317 is a prime.

It is a super-2 number, since 2×669506381² = 896477588399434322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (669506351) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334753190 + 334753191.

It is an arithmetic number, because the mean of its divisors is an integer number (334753191).

Almost surely, 2^669506381 is an apocalyptic number.

It is an amenable number.

669506381 is a deficient number, since it is larger than the sum of its proper divisors (1).

669506381 is an equidigital number, since it uses as much as digits as its factorization.

669506381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 233280, while the sum is 44.

The square root of 669506381 is about 25874.8213713641. The cubic root of 669506381 is about 874.8190672423.

The spelling of 669506381 in words is "six hundred sixty-nine million, five hundred six thousand, three hundred eighty-one".