1644630421 has 8 divisors (see below), whose sum is σ = 1891550720. Its totient is φ = 1400703408.

The previous prime is 1644630419. The next prime is 1644630467. The reversal of 1644630421 is 1240364461.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1644630421 - 2¹ = 1644630419 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 (1644630401) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 747141 + ... + 749338.

It is an arithmetic number, because the mean of its divisors is an integer number (236443840).

Almost surely, 2^1644630421 is an apocalyptic number.

It is an amenable number.

1644630421 is a deficient number, since it is larger than the sum of its proper divisors (246920299).

1644630421 is a wasteful number, since it uses less digits than its factorization.

1644630421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1496643.

The product of its (nonzero) digits is 13824, while the sum is 31.

The square root of 1644630421 is about 40554.0432139633. The cubic root of 1644630421 is about 1180.3825296705.

Adding to 1644630421 its reverse (1240364461), we get a palindrome (2884994882).

The spelling of 1644630421 in words is "one billion, six hundred forty-four million, six hundred thirty thousand, four hundred twenty-one".