390649669 has 2 divisors, whose sum is σ = 390649670. Its totient is φ = 390649668.

The previous prime is 390649667. The next prime is 390649717. The reversal of 390649669 is 966946093.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 214769025 + 175880644 = 14655^2 + 13262^2 .

It is a cyclic number.

It is not a de Polignac number, because 390649669 - 2¹ = 390649667 is a prime.

It is a super-2 number, since 2×390649669² = 305214327779619122, which contains 22 as substring.

Together with 390649667, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (390649661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195324834 + 195324835.

It is an arithmetic number, because the mean of its divisors is an integer number (195324835).

Almost surely, 2^390649669 is an apocalyptic number.

It is an amenable number.

390649669 is a deficient number, since it is larger than the sum of its proper divisors (1).

390649669 is an equidigital number, since it uses as much as digits as its factorization.

390649669 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1889568, while the sum is 52.

The square root of 390649669 is about 19764.8594480204. The cubic root of 390649669 is about 731.0198225159.

The spelling of 390649669 in words is "three hundred ninety million, six hundred forty-nine thousand, six hundred sixty-nine".