1291990 has 16 divisors (see below), whose sum is σ = 2657952. Its totient is φ = 442944.

The previous prime is 1291967. The next prime is 1291991. The reversal of 1291990 is 991921.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1291991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9159 + ... + 9298.

It is an arithmetic number, because the mean of its divisors is an integer number (166122).

2^1291990 is an apocalyptic number.

1291990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1291990 is an abundant number, since it is smaller than the sum of its proper divisors (1365962).

1291990 is a wasteful number, since it uses less digits than its factorization.

1291990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18471.

The product of its (nonzero) digits is 1458, while the sum is 31.

The square root of 1291990 is about 1136.6573802162. The cubic root of 1291990 is about 108.9146710357.

The spelling of 1291990 in words is "one million, two hundred ninety-one thousand, nine hundred ninety".