668514421 has 4 divisors (see below), whose sum is σ = 684061312. Its totient is φ = 652967532.

The previous prime is 668514391. The next prime is 668514439. The reversal of 668514421 is 124415866.

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, and also an emirpimes, since its reverse is a distinct semiprime: 124415866 = 2 ⋅62207933.

It is a cyclic number.

It is not a de Polignac number, because 668514421 - 2¹³ = 668506229 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 (668514521) 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 3 ways as a sum of consecutive naturals, for example, 7773381 + ... + 7773466.

It is an arithmetic number, because the mean of its divisors is an integer number (171015328).

Almost surely, 2^668514421 is an apocalyptic number.

It is an amenable number.

668514421 is a deficient number, since it is larger than the sum of its proper divisors (15546891).

668514421 is a wasteful number, since it uses less digits than its factorization.

668514421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15546890.

The product of its digits is 46080, while the sum is 37.

The square root of 668514421 is about 25855.6458244616. The cubic root of 668514421 is about 874.3868012832.

The spelling of 668514421 in words is "six hundred sixty-eight million, five hundred fourteen thousand, four hundred twenty-one".