1257840 has 60 divisors (see below), whose sum is σ = 4226664. Its totient is φ = 335232.

The previous prime is 1257829. The next prime is 1257853. The reversal of 1257840 is 487521.

It is a tau number, because it is divible by the number of its divisors (60).

It is a super-2 number, since 2×1257840² = 3164322931200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 154 + ... + 1593.

2^1257840 is an apocalyptic number.

1257840 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 1257840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2113332).

1257840 is an abundant number, since it is smaller than the sum of its proper divisors (2968824).

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

1257840 is a wasteful number, since it uses less digits than its factorization.

1257840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1766 (or 1757 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 1257840 is about 1121.5346628616. The cubic root of 1257840 is about 107.9464755354.

The spelling of 1257840 in words is "one million, two hundred fifty-seven thousand, eight hundred forty".