1628681 has 4 divisors (see below), whose sum is σ = 1632000. Its totient is φ = 1625364.

The previous prime is 1628633. The next prime is 1628689. The reversal of 1628681 is 1868261.

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 a de Polignac number, because none of the positive numbers 2^k-1628681 is a prime.

It is a super-2 number, since 2×1628681² = 5305203599522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a plaindrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (1628689) 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, 761 + ... + 1958.

It is an arithmetic number, because the mean of its divisors is an integer number (408000).

2^1628681 is an apocalyptic number.

It is an amenable number.

1628681 is a deficient number, since it is larger than the sum of its proper divisors (3319).

1628681 is an equidigital number, since it uses as much as digits as its factorization.

1628681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3318.

The product of its digits is 4608, while the sum is 32.

The square root of 1628681 is about 1276.1978686708. The cubic root of 1628681 is about 117.6554393687.

The spelling of 1628681 in words is "one million, six hundred twenty-eight thousand, six hundred eighty-one".