1281630 has 64 divisors (see below), whose sum is σ = 3732480. Its totient is φ = 274944.

The previous prime is 1281587. The next prime is 1281649. The reversal of 1281630 is 361821.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1281597 and 1281606.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3391 + ... + 3749.

It is an arithmetic number, because the mean of its divisors is an integer number (58320).

2^1281630 is an apocalyptic number.

1281630 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1281630, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1866240).

1281630 is an abundant number, since it is smaller than the sum of its proper divisors (2450850).

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

1281630 is a wasteful number, since it uses less digits than its factorization.

1281630 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 393.

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 1281630 is about 1132.0909857428. The cubic root of 1281630 is about 108.6227736631.

The spelling of 1281630 in words is "one million, two hundred eighty-one thousand, six hundred thirty".