1980651 has 4 divisors (see below), whose sum is σ = 2640872. Its totient is φ = 1320432.

The previous prime is 1980637. The next prime is 1980659. The reversal of 1980651 is 1560891.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1560891 = 3 ⋅520297.

It is not a de Polignac number, because 1980651 - 2⁷ = 1980523 is a prime.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1980659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 330106 + ... + 330111.

It is an arithmetic number, because the mean of its divisors is an integer number (660218).

2^1980651 is an apocalyptic number.

1980651 is a deficient number, since it is larger than the sum of its proper divisors (660221).

1980651 is an equidigital number, since it uses as much as digits as its factorization.

1980651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 660220.

The product of its (nonzero) digits is 2160, while the sum is 30.

The square root of 1980651 is about 1407.3560317134. The cubic root of 1980651 is about 125.5844841003.

The spelling of 1980651 in words is "one million, nine hundred eighty thousand, six hundred fifty-one".