1644631401 has 32 divisors (see below), whose sum is σ = 2599833600. Its totient is φ = 905224320.

The previous prime is 1644631337. The next prime is 1644631421. The reversal of 1644631401 is 1041364461.

It is not a de Polignac number, because 1644631401 - 2⁶ = 1644631337 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1644631421) 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 31 ways as a sum of consecutive naturals, for example, 55930 + ... + 80108.

It is an arithmetic number, because the mean of its divisors is an integer number (81244800).

Almost surely, 2^1644631401 is an apocalyptic number.

It is an amenable number.

1644631401 is a deficient number, since it is larger than the sum of its proper divisors (955202199).

1644631401 is a wasteful number, since it uses less digits than its factorization.

1644631401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24309.

The product of its (nonzero) digits is 6912, while the sum is 30.

The square root of 1644631401 is about 40554.0552966038. The cubic root of 1644631401 is about 1180.3827641253.

Adding to 1644631401 its reverse (1041364461), we get a palindrome (2685995862).

The spelling of 1644631401 in words is "one billion, six hundred forty-four million, six hundred thirty-one thousand, four hundred one".