1991229 has 8 divisors (see below), whose sum is σ = 2726880. Its totient is φ = 1291536.

The previous prime is 1991189. The next prime is 1991239. The reversal of 1991229 is 9221991.

1991229 = T₁₉₄ + T₁₉₅ + ... + T₂₆₇.

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

It is not a de Polignac number, because 1991229 - 2⁸ = 1990973 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1991229.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1991239) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8859 + ... + 9080.

It is an arithmetic number, because the mean of its divisors is an integer number (340860).

2^1991229 is an apocalyptic number.

It is an amenable number.

1991229 is a deficient number, since it is larger than the sum of its proper divisors (735651).

1991229 is a wasteful number, since it uses less digits than its factorization.

1991229 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17979.

The product of its digits is 2916, while the sum is 33.

The square root of 1991229 is about 1411.1091382313. The cubic root of 1991229 is about 125.8076556331.

The spelling of 1991229 in words is "one million, nine hundred ninety-one thousand, two hundred twenty-nine".