1990138 has 8 divisors (see below), whose sum is σ = 3081600. Its totient is φ = 962940.

The previous prime is 1990133. The next prime is 1990141. The reversal of 1990138 is 8310991.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is not an unprimeable number, because it can be changed into a prime (1990133) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15988 + ... + 16111.

It is an arithmetic number, because the mean of its divisors is an integer number (385200).

2^1990138 is an apocalyptic number.

1990138 is a deficient number, since it is larger than the sum of its proper divisors (1091462).

1990138 is a wasteful number, since it uses less digits than its factorization.

1990138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32132.

The product of its (nonzero) digits is 1944, while the sum is 31.

The square root of 1990138 is about 1410.7225099218. The cubic root of 1990138 is about 125.7846746454.

The spelling of 1990138 in words is "one million, nine hundred ninety thousand, one hundred thirty-eight".