1639998 has 24 divisors (see below), whose sum is σ = 3580200. Its totient is φ = 542544.

The previous prime is 1639991. The next prime is 1639999. The reversal of 1639998 is 8999361.

1639998 is a `hidden beast` number, since 1 + 639 + 9 + 9 + 8 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1639991) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2968 + ... + 3476.

It is an arithmetic number, because the mean of its divisors is an integer number (149175).

2^1639998 is an apocalyptic number.

1639998 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1639998 is an abundant number, since it is smaller than the sum of its proper divisors (1940202).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1639998 is a wasteful number, since it uses less digits than its factorization.

1639998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 696 (or 693 counting only the distinct ones).

The product of its digits is 104976, while the sum is 45.

The square root of 1639998 is about 1280.6240666175. The cubic root of 1639998 is about 117.9273228614.

The spelling of 1639998 in words is "one million, six hundred thirty-nine thousand, nine hundred ninety-eight".