667821245 has 54 divisors (see below), whose sum is σ = 1017460602. Its totient is φ = 419380416.

The previous prime is 667821223. The next prime is 667821247. The reversal of 667821245 is 542128766.

It can be written as a sum of positive squares in 3 ways, for example, as 3161284 + 664659961 = 1778^2 + 25781^2 .

It is not a de Polignac number, because 667821245 - 2²² = 663626941 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667821247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 5258372 + ... + 5258498.

It is an arithmetic number, because the mean of its divisors is an integer number (18841863).

Almost surely, 2^667821245 is an apocalyptic number.

667821245 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

667821245 is a deficient number, since it is larger than the sum of its proper divisors (349639357).

667821245 is a wasteful number, since it uses less digits than its factorization.

667821245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 299 (or 152 counting only the distinct ones).

The product of its digits is 161280, while the sum is 41.

The square root of 667821245 is about 25842.2376159651. The cubic root of 667821245 is about 874.0844824227.

The spelling of 667821245 in words is "six hundred sixty-seven million, eight hundred twenty-one thousand, two hundred forty-five".