1291928 has 32 divisors (see below), whose sum is σ = 2702160. Its totient is φ = 574080.

The previous prime is 1291909. The next prime is 1291931. The reversal of 1291928 is 8291921.

1291928 = T₂₂ + T₂₃ + ... + T₁₉₇.

It is a happy number.

It is a Smith number, since the sum of its digits (32) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 1291894 and 1291903.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4526 + ... + 4802.

2^1291928 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1291928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1351080).

1291928 is an abundant number, since it is smaller than the sum of its proper divisors (1410232).

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

1291928 is a wasteful number, since it uses less digits than its factorization.

1291928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 347 (or 343 counting only the distinct ones).

The product of its digits is 2592, while the sum is 32.

The square root of 1291928 is about 1136.6301069389. The cubic root of 1291928 is about 108.9129288092.

The spelling of 1291928 in words is "one million, two hundred ninety-one thousand, nine hundred twenty-eight".