1280400 has 120 divisors (see below), whose sum is σ = 4520544. Its totient is φ = 307200.

The previous prime is 1280399. The next prime is 1280401. The reversal of 1280400 is 40821.

It is an interprime number because it is at equal distance from previous prime (1280399) and next prime (1280401).

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 1280400.

It is not an unprimeable number, because it can be changed into a prime (1280401) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13152 + ... + 13248.

2^1280400 is an apocalyptic number.

1280400 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 1280400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2260272).

1280400 is an abundant number, since it is smaller than the sum of its proper divisors (3240144).

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

1280400 is a wasteful number, since it uses less digits than its factorization.

1280400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129 (or 118 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 1280400 is about 1131.5476127853. The cubic root of 1280400 is about 108.5880135593.

It can be divided in two parts, 1280 and 400, that multiplied together give a cube (512000 = 80³).

The spelling of 1280400 in words is "one million, two hundred eighty thousand, four hundred".