1639988 has 24 divisors (see below), whose sum is σ = 3370752. Its totient is φ = 683424.

The previous prime is 1639987. The next prime is 1639991. The reversal of 1639988 is 8899361.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1639987) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 245 + ... + 1827.

It is an arithmetic number, because the mean of its divisors is an integer number (140448).

2^1639988 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1639988, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1685376).

1639988 is an abundant number, since it is smaller than the sum of its proper divisors (1730764).

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

1639988 is a wasteful number, since it uses less digits than its factorization.

1639988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1631 (or 1629 counting only the distinct ones).

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

The square root of 1639988 is about 1280.6201622651. The cubic root of 1639988 is about 117.9270831710.

It can be divided in two parts, 16 and 39988, that added together give a palindrome (40004).

The spelling of 1639988 in words is "one million, six hundred thirty-nine thousand, nine hundred eighty-eight".