1990549 has 4 divisors (see below), whose sum is σ = 2171520. Its totient is φ = 1809580.

The previous prime is 1990543. The next prime is 1990553. The reversal of 1990549 is 9450991.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 9450991 = 11 ⋅859181.

It is a cyclic number.

It is not a de Polignac number, because 1990549 - 2¹⁹ = 1466261 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1990543) 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, 90469 + ... + 90490.

It is an arithmetic number, because the mean of its divisors is an integer number (542880).

2^1990549 is an apocalyptic number.

It is an amenable number.

1990549 is a deficient number, since it is larger than the sum of its proper divisors (180971).

1990549 is a wasteful number, since it uses less digits than its factorization.

1990549 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180970.

The product of its (nonzero) digits is 14580, while the sum is 37.

The square root of 1990549 is about 1410.8681724385. The cubic root of 1990549 is about 125.7933329969.

The spelling of 1990549 in words is "one million, nine hundred ninety thousand, five hundred forty-nine".