1668367521 has 12 divisors (see below), whose sum is σ = 2410716048. Its totient is φ = 1111851864.

The previous prime is 1668367483. The next prime is 1668367543. The reversal of 1668367521 is 1257638661.

1668367521 is a `hidden beast` number, since 1 + 6 + 68 + 3 + 67 + 521 = 666.

It is not a de Polignac number, because 1668367521 - 2⁹ = 1668367009 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1668365521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4615 + ... + 57948.

It is an arithmetic number, because the mean of its divisors is an integer number (200893004).

Almost surely, 2^1668367521 is an apocalyptic number.

It is an amenable number.

1668367521 is a deficient number, since it is larger than the sum of its proper divisors (742348527).

1668367521 is a wasteful number, since it uses less digits than its factorization.

1668367521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65532 (or 65529 counting only the distinct ones).

The product of its digits is 362880, while the sum is 45.

The square root of 1668367521 is about 40845.6548607070. The cubic root of 1668367521 is about 1186.0342815370.

The spelling of 1668367521 in words is "one billion, six hundred sixty-eight million, three hundred sixty-seven thousand, five hundred twenty-one".