1991224 has 8 divisors (see below), whose sum is σ = 3733560. Its totient is φ = 995608.

The previous prime is 1991189. The next prime is 1991239. The reversal of 1991224 is 4221991.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (8).

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 1991192 and 1991201.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 124444 + ... + 124459.

It is an arithmetic number, because the mean of its divisors is an integer number (466695).

2^1991224 is an apocalyptic number.

It is an amenable number.

1991224 is a deficient number, since it is larger than the sum of its proper divisors (1742336).

1991224 is a wasteful number, since it uses less digits than its factorization.

1991224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 248909 (or 248905 counting only the distinct ones).

The product of its digits is 1296, while the sum is 28.

The square root of 1991224 is about 1411.1073665742. The cubic root of 1991224 is about 125.8075503315.

The spelling of 1991224 in words is "one million, nine hundred ninety-one thousand, two hundred twenty-four".