15998638 has 4 divisors (see below), whose sum is σ = 23997960. Its totient is φ = 7999318.

The previous prime is 15998629. The next prime is 15998641. The reversal of 15998638 is 83689951.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 83689951 = 97 ⋅862783.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 15998591 and 15998600.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3999658 + ... + 3999661.

It is an arithmetic number, because the mean of its divisors is an integer number (5999490).

Almost surely, 2^15998638 is an apocalyptic number.

15998638 is a deficient number, since it is larger than the sum of its proper divisors (7999322).

15998638 is an equidigital number, since it uses as much as digits as its factorization.

15998638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7999321.

The product of its digits is 466560, while the sum is 49.

The square root of 15998638 is about 3999.8297463767. The cubic root of 15998638 is about 251.9770597241.

The spelling of 15998638 in words is "fifteen million, nine hundred ninety-eight thousand, six hundred thirty-eight".