1291920 has 80 divisors (see below), whose sum is σ = 4583040. Its totient is φ = 294912.

The previous prime is 1291909. The next prime is 1291931. The reversal of 1291920 is 291921.

It is an interprime number because it is at equal distance from previous prime (1291909) and next prime (1291931).

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an Ulam number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1296 + ... + 2064.

It is an arithmetic number, because the mean of its divisors is an integer number (57288).

2^1291920 is an apocalyptic number.

1291920 is a gapful number since it is divisible by the number (10) 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 1291920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2291520).

1291920 is an abundant number, since it is smaller than the sum of its proper divisors (3291120).

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

1291920 is a wasteful number, since it uses less digits than its factorization.

1291920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 792 (or 786 counting only the distinct ones).

The product of its (nonzero) digits is 324, while the sum is 24.

The square root of 1291920 is about 1136.6265877587. The cubic root of 1291920 is about 108.9127040017.

Subtracting from 1291920 its reverse (291921), we obtain a palindrome (999999).

It can be divided in two parts, 1291 and 920, that added together give a triangular number (2211 = T₆₆).

The spelling of 1291920 in words is "one million, two hundred ninety-one thousand, nine hundred twenty".