668284993 has 4 divisors (see below), whose sum is σ = 669680640. Its totient is φ = 666889348.

The previous prime is 668284927. The next prime is 668284999. The reversal of 668284993 is 399482866.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 668284993 - 2¹⁷ = 668153921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (668284999) 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, 697105 + ... + 698062.

It is an arithmetic number, because the mean of its divisors is an integer number (167420160).

Almost surely, 2^668284993 is an apocalyptic number.

It is an amenable number.

668284993 is a deficient number, since it is larger than the sum of its proper divisors (1395647).

668284993 is a wasteful number, since it uses less digits than its factorization.

668284993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1395646.

The product of its digits is 4478976, while the sum is 55.

The square root of 668284993 is about 25851.2087338291. The cubic root of 668284993 is about 874.2867626691.

The spelling of 668284993 in words is "six hundred sixty-eight million, two hundred eighty-four thousand, nine hundred ninety-three".