1628581 has 4 divisors (see below), whose sum is σ = 1631872. Its totient is φ = 1625292.

The previous prime is 1628579. The next prime is 1628587. The reversal of 1628581 is 1858261.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1628581 - 2¹ = 1628579 is a prime.

It is a super-2 number, since 2×1628581² = 5304552147122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1628587) 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 in 3 ways as a sum of consecutive naturals, for example, 735 + ... + 1948.

It is an arithmetic number, because the mean of its divisors is an integer number (407968).

2^1628581 is an apocalyptic number.

It is an amenable number.

1628581 is a deficient number, since it is larger than the sum of its proper divisors (3291).

1628581 is an equidigital number, since it uses as much as digits as its factorization.

1628581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3290.

The product of its digits is 3840, while the sum is 31.

The square root of 1628581 is about 1276.1586891919. The cubic root of 1628581 is about 117.6530313291.

It can be divided in two parts, 1628 and 581, that added together give a square (2209 = 47²).

The spelling of 1628581 in words is "one million, six hundred twenty-eight thousand, five hundred eighty-one".