1999538 has 4 divisors (see below), whose sum is σ = 2999310. Its totient is φ = 999768.

The previous prime is 1999537. The next prime is 1999549. The reversal of 1999538 is 8359991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8359991 = 311 ⋅26881.

It can be written as a sum of positive squares in only one way, i.e., 1315609 + 683929 = 1147^2 + 827^2 .

It is not an unprimeable number, because it can be changed into a prime (1999537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499883 + ... + 499886.

2^1999538 is an apocalyptic number.

1999538 is a deficient number, since it is larger than the sum of its proper divisors (999772).

1999538 is an equidigital number, since it uses as much as digits as its factorization.

1999538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 999771.

The product of its digits is 87480, while the sum is 44.

The square root of 1999538 is about 1414.0502112726. The cubic root of 1999538 is about 125.9824028503.

The spelling of 1999538 in words is "one million, nine hundred ninety-nine thousand, five hundred thirty-eight".