1991626 has 32 divisors (see below), whose sum is σ = 3806208. Its totient is φ = 760320.

The previous prime is 1991623. The next prime is 1991641. The reversal of 1991626 is 6261991.

It is a junction number, because it is equal to n+sod(n) for n = 1991591 and 1991600.

It is not an unprimeable number, because it can be changed into a prime (1991623) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5466 + ... + 5818.

It is an arithmetic number, because the mean of its divisors is an integer number (118944).

2^1991626 is an apocalyptic number.

1991626 is the 706-th decagonal number.

1991626 is a deficient number, since it is larger than the sum of its proper divisors (1814582).

1991626 is a wasteful number, since it uses less digits than its factorization.

1991626 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 406.

The product of its digits is 5832, while the sum is 34.

The square root of 1991626 is about 1411.2498007086. The cubic root of 1991626 is about 125.8160160176.

The spelling of 1991626 in words is "one million, nine hundred ninety-one thousand, six hundred twenty-six".