1990658 has 4 divisors (see below), whose sum is σ = 2985990. Its totient is φ = 995328.

The previous prime is 1990657. The next prime is 1990661. The reversal of 1990658 is 8560991.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 1646089 + 344569 = 1283^2 + 587^2 .

It is not an unprimeable number, because it can be changed into a prime (1990657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 497663 + ... + 497666.

2^1990658 is an apocalyptic number.

1990658 is a deficient number, since it is larger than the sum of its proper divisors (995332).

1990658 is an equidigital number, since it uses as much as digits as its factorization.

1990658 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 995331.

The product of its (nonzero) digits is 19440, while the sum is 38.

The square root of 1990658 is about 1410.9068006073. The cubic root of 1990658 is about 125.7956290507.

The spelling of 1990658 in words is "one million, nine hundred ninety thousand, six hundred fifty-eight".