16438421638 has 4 divisors (see below), whose sum is σ = 24657632460. Its totient is φ = 8219210818.

The previous prime is 16438421627. The next prime is 16438421639. The reversal of 16438421638 is 83612483461.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16438421639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4109605408 + ... + 4109605411.

It is an arithmetic number, because the mean of its divisors is an integer number (6164408115).

Almost surely, 2^16438421638 is an apocalyptic number.

16438421638 is a deficient number, since it is larger than the sum of its proper divisors (8219210822).

16438421638 is an equidigital number, since it uses as much as digits as its factorization.

16438421638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8219210821.

The product of its digits is 663552, while the sum is 46.

The spelling of 16438421638 in words is "sixteen billion, four hundred thirty-eight million, four hundred twenty-one thousand, six hundred thirty-eight".