1291428 has 36 divisors (see below), whose sum is σ = 3379740. Its totient is φ = 415296.

The previous prime is 1291421. The next prime is 1291447. The reversal of 1291428 is 8241921.

It can be written as a sum of positive squares in 2 ways, for example, as 831744 + 459684 = 912^2 + 678^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a plaindrome in base 14.

It is not an unprimeable number, because it can be changed into a prime (1291421) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 426 + ... + 1662.

2^1291428 is an apocalyptic number.

1291428 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1291428, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1689870).

1291428 is an abundant number, since it is smaller than the sum of its proper divisors (2088312).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1291428 is a wasteful number, since it uses less digits than its factorization.

1291428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1276 (or 1271 counting only the distinct ones).

The product of its digits is 1152, while the sum is 27.

The square root of 1291428 is about 1136.4101372304. The cubic root of 1291428 is about 108.8988765578.

The spelling of 1291428 in words is "one million, two hundred ninety-one thousand, four hundred twenty-eight".