1664621637 has 16 divisors (see below), whose sum is σ = 2543099520. Its totient is φ = 948762432.

The previous prime is 1664621627. The next prime is 1664621641. The reversal of 1664621637 is 7361264661.

It is not a de Polignac number, because 1664621637 - 2¹⁴ = 1664605253 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1664621617) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 93718 + ... + 110055.

It is an arithmetic number, because the mean of its divisors is an integer number (158943720).

Almost surely, 2^1664621637 is an apocalyptic number.

It is an amenable number.

1664621637 is a deficient number, since it is larger than the sum of its proper divisors (878477883).

1664621637 is a wasteful number, since it uses less digits than its factorization.

1664621637 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204172.

The product of its digits is 217728, while the sum is 42.

The square root of 1664621637 is about 40799.7749626147. The cubic root of 1664621637 is about 1185.1459728668.

It can be divided in two parts, 16646 and 21637, that added together give a palindrome (38283).

The spelling of 1664621637 in words is "one billion, six hundred sixty-four million, six hundred twenty-one thousand, six hundred thirty-seven".