1668389421 has 8 divisors (see below), whose sum is σ = 2226226464. Its totient is φ = 1111406000.

The previous prime is 1668389419. The next prime is 1668389473. The reversal of 1668389421 is 1249838661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1668389421 - 2¹ = 1668389419 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1668389521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 208830 + ... + 216671.

It is an arithmetic number, because the mean of its divisors is an integer number (278278308).

Almost surely, 2^1668389421 is an apocalyptic number.

It is an amenable number.

1668389421 is a deficient number, since it is larger than the sum of its proper divisors (557837043).

1668389421 is a wasteful number, since it uses less digits than its factorization.

1668389421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 426811.

The product of its digits is 497664, while the sum is 48.

The square root of 1668389421 is about 40845.9229421983. The cubic root of 1668389421 is about 1186.0394710485.

The spelling of 1668389421 in words is "one billion, six hundred sixty-eight million, three hundred eighty-nine thousand, four hundred twenty-one".