1638998 has 4 divisors (see below), whose sum is σ = 2458500. Its totient is φ = 819498.

The previous prime is 1638991. The next prime is 1639019. The reversal of 1638998 is 8998361.

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 (1638991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 409748 + ... + 409751.

It is an arithmetic number, because the mean of its divisors is an integer number (614625).

2^1638998 is an apocalyptic number.

1638998 is a deficient number, since it is larger than the sum of its proper divisors (819502).

1638998 is an equidigital number, since it uses as much as digits as its factorization.

1638998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 819501.

The product of its digits is 93312, while the sum is 44.

The square root of 1638998 is about 1280.2335724390. The cubic root of 1638998 is about 117.9033489907.

The spelling of 1638998 in words is "one million, six hundred thirty-eight thousand, nine hundred ninety-eight".