1281990 has 32 divisors (see below), whose sum is σ = 3108096. Its totient is φ = 338400.

The previous prime is 1281983. The next prime is 1282007. The reversal of 1281990 is 991821.

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an Ulam number.

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, 4389 + ... + 4671.

It is an arithmetic number, because the mean of its divisors is an integer number (97128).

2^1281990 is an apocalyptic number.

1281990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1281990 is an abundant number, since it is smaller than the sum of its proper divisors (1826106).

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

1281990 is a wasteful number, since it uses less digits than its factorization.

1281990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 444.

The product of its (nonzero) digits is 1296, while the sum is 30.

The square root of 1281990 is about 1132.2499724001. The cubic root of 1281990 is about 108.6329431446.

The spelling of 1281990 in words is "one million, two hundred eighty-one thousand, nine hundred ninety".