421721668 has 12 divisors (see below), whose sum is σ = 744910992. Its totient is φ = 208889960.

The previous prime is 421721653. The next prime is 421721693. The reversal of 421721668 is 866127124.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 492238 + ... + 493093.

It is an arithmetic number, because the mean of its divisors is an integer number (62075916).

Almost surely, 2^421721668 is an apocalyptic number.

It is an amenable number.

421721668 is a deficient number, since it is larger than the sum of its proper divisors (323189324).

421721668 is a wasteful number, since it uses less digits than its factorization.

421721668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 985442 (or 985440 counting only the distinct ones).

The product of its digits is 32256, while the sum is 37.

The square root of 421721668 is about 20535.8629718841. The cubic root of 421721668 is about 749.9091255822.

The spelling of 421721668 in words is "four hundred twenty-one million, seven hundred twenty-one thousand, six hundred sixty-eight".