1626661 has 4 divisors (see below), whose sum is σ = 1632172. Its totient is φ = 1621152.

The previous prime is 1626649. The next prime is 1626673. The reversal of 1626661 is 1666261.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (1626649) and next prime (1626673).

It can be written as a sum of positive squares in 2 ways, for example, as 260100 + 1366561 = 510^2 + 1169^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1626661 is a prime.

It is a Duffinian number.

1626661 is a lucky number.

It is a nialpdrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1626461) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2286 + ... + 2911.

It is an arithmetic number, because the mean of its divisors is an integer number (408043).

2^1626661 is an apocalyptic number.

It is an amenable number.

1626661 is a deficient number, since it is larger than the sum of its proper divisors (5511).

1626661 is an equidigital number, since it uses as much as digits as its factorization.

1626661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5510.

The product of its digits is 2592, while the sum is 28.

The square root of 1626661 is about 1275.4062098014. The cubic root of 1626661 is about 117.6067778422.

The spelling of 1626661 in words is "one million, six hundred twenty-six thousand, six hundred sixty-one".