17728621138 has 4 divisors (see below), whose sum is σ = 26592931710. Its totient is φ = 8864310568.

The previous prime is 17728621129. The next prime is 17728621147. The reversal of 17728621138 is 83112682771.

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

It is an interprime number because it is at equal distance from previous prime (17728621129) and next prime (17728621147).

It can be written as a sum of positive squares in only one way, i.e., 12282623929 + 5445997209 = 110827^2 + 73797^2 .

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 4432155283 + ... + 4432155286.

Almost surely, 2^17728621138 is an apocalyptic number.

17728621138 is a deficient number, since it is larger than the sum of its proper divisors (8864310572).

17728621138 is an equidigital number, since it uses as much as digits as its factorization.

17728621138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8864310571.

The product of its digits is 225792, while the sum is 46.

The spelling of 17728621138 in words is "seventeen billion, seven hundred twenty-eight million, six hundred twenty-one thousand, one hundred thirty-eight".