1664204421 has 16 divisors (see below), whose sum is σ = 2425536000. Its totient is φ = 1006577520.

The previous prime is 1664204413. The next prime is 1664204489. The reversal of 1664204421 is 1244024661.

It is a happy number.

1664204421 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 1664204421 - 2³ = 1664204413 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1664204401) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 34065 + ... + 66998.

It is an arithmetic number, because the mean of its divisors is an integer number (151596000).

Almost surely, 2^1664204421 is an apocalyptic number.

1664204421 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1664204421 is a deficient number, since it is larger than the sum of its proper divisors (761331579).

1664204421 is a wasteful number, since it uses less digits than its factorization.

1664204421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101576.

The product of its (nonzero) digits is 9216, while the sum is 30.

The square root of 1664204421 is about 40794.6616728218. The cubic root of 1664204421 is about 1185.0469507293.

The spelling of 1664204421 in words is "one billion, six hundred sixty-four million, two hundred four thousand, four hundred twenty-one".