1291864 has 64 divisors (see below), whose sum is σ = 3110400. Its totient is φ = 489984.

The previous prime is 1291861. The next prime is 1291877. The reversal of 1291864 is 4681921.

1291864 = T₈₅ + T₈₆ + ... + T₂₀₂.

It is a happy number.

Its product of digits (3456) is a multiple of the sum of its prime divisors (108).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1291861) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 21867 + ... + 21925.

It is an arithmetic number, because the mean of its divisors is an integer number (48600).

2^1291864 is an apocalyptic number.

1291864 is a gapful number since it is divisible by the number (14) 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 1291864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1555200).

1291864 is an abundant number, since it is smaller than the sum of its proper divisors (1818536).

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

1291864 is a wasteful number, since it uses less digits than its factorization.

1291864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 112 (or 108 counting only the distinct ones).

The product of its digits is 3456, while the sum is 31.

The square root of 1291864 is about 1136.6019531921. The cubic root of 1291864 is about 108.9111303233.

The spelling of 1291864 in words is "one million, two hundred ninety-one thousand, eight hundred sixty-four".