1663446821 has 16 divisors (see below), whose sum is σ = 1775960640. Its totient is φ = 1552615680.

The previous prime is 1663446809. The next prime is 1663446833. The reversal of 1663446821 is 1286443661.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1663446809) and next prime (1663446833).

It is a cyclic number.

It is not a de Polignac number, because 1663446821 - 2²⁶ = 1596337957 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 (1663442821) 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, 2011010 + ... + 2011836.

It is an arithmetic number, because the mean of its divisors is an integer number (110997540).

Almost surely, 2^1663446821 is an apocalyptic number.

It is an amenable number.

1663446821 is a deficient number, since it is larger than the sum of its proper divisors (112513819).

1663446821 is a wasteful number, since it uses less digits than its factorization.

1663446821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1684.

The product of its digits is 165888, while the sum is 41.

The square root of 1663446821 is about 40785.3750871559. The cubic root of 1663446821 is about 1184.8670994586.

The spelling of 1663446821 in words is "one billion, six hundred sixty-three million, four hundred forty-six thousand, eight hundred twenty-one".