1581002 has 4 divisors (see below), whose sum is σ = 2371506. Its totient is φ = 790500.

The previous prime is 1580987. The next prime is 1581007. The reversal of 1581002 is 2001851.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 2001851 = 23 ⋅87037.

It can be written as a sum of positive squares in only one way, i.e., 1413721 + 167281 = 1189^2 + 409^2 .

It is not an unprimeable number, because it can be changed into a prime (1581007) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 395249 + ... + 395252.

2^1581002 is an apocalyptic number.

1581002 is a deficient number, since it is larger than the sum of its proper divisors (790504).

1581002 is an equidigital number, since it uses as much as digits as its factorization.

1581002 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 790503.

The product of its (nonzero) digits is 80, while the sum is 17.

The square root of 1581002 is about 1257.3790200254. The cubic root of 1581002 is about 116.4959444025.

Adding to 1581002 its reverse (2001851), we get a palindrome (3582853).

The spelling of 1581002 in words is "one million, five hundred eighty-one thousand, two".