1991554 has 8 divisors (see below), whose sum is σ = 3004560. Its totient is φ = 990036.

The previous prime is 1991551. The next prime is 1991573. The reversal of 1991554 is 4551991.

It is a happy number.

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

It is not an unprimeable number, because it can be changed into a prime (1991551) 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, 2424 + ... + 3139.

It is an arithmetic number, because the mean of its divisors is an integer number (375570).

2^1991554 is an apocalyptic number.

1991554 is a deficient number, since it is larger than the sum of its proper divisors (1013006).

1991554 is a wasteful number, since it uses less digits than its factorization.

1991554 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5744.

The product of its digits is 8100, while the sum is 34.

The square root of 1991554 is about 1411.2242911742. The cubic root of 1991554 is about 125.8144998591.

The spelling of 1991554 in words is "one million, nine hundred ninety-one thousand, five hundred fifty-four".