1991602 has 4 divisors (see below), whose sum is σ = 2987406. Its totient is φ = 995800.

The previous prime is 1991597. The next prime is 1991603. The reversal of 1991602 is 2061991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 2061991 = 59 ⋅34949.

It can be written as a sum of positive squares in only one way, i.e., 1147041 + 844561 = 1071^2 + 919^2 .

It is not an unprimeable number, because it can be changed into a prime (1991603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 497899 + ... + 497902.

2^1991602 is an apocalyptic number.

1991602 is a deficient number, since it is larger than the sum of its proper divisors (995804).

1991602 is an equidigital number, since it uses as much as digits as its factorization.

1991602 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 995803.

The product of its (nonzero) digits is 972, while the sum is 28.

The square root of 1991602 is about 1411.2412975817. The cubic root of 1991602 is about 125.8155106355.

The spelling of 1991602 in words is "one million, nine hundred ninety-one thousand, six hundred two".