1261440 has 128 divisors (see below), whose sum is σ = 4528800. Its totient is φ = 331776.

The previous prime is 1261427. The next prime is 1261459. The reversal of 1261440 is 441621.

1261440 is a `hidden beast` number, since 12 + 614 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent 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, 17244 + ... + 17316.

2^1261440 is an apocalyptic number.

1261440 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 1261440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2264400).

1261440 is an abundant number, since it is smaller than the sum of its proper divisors (3267360).

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

1261440 is an equidigital number, since it uses as much as digits as its factorization.

1261440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101 (or 83 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 1261440 is about 1123.1384598526. The cubic root of 1261440 is about 108.0493601531.

The spelling of 1261440 in words is "one million, two hundred sixty-one thousand, four hundred forty".