1980921 has 16 divisors (see below), whose sum is σ = 2903040. Its totient is φ = 1195920.

The previous prime is 1980919. The next prime is 1980929. The reversal of 1980921 is 1290891.

It is not a de Polignac number, because 1980921 - 2¹ = 1980919 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1980929) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 556 + ... + 2066.

It is an arithmetic number, because the mean of its divisors is an integer number (181440).

2^1980921 is an apocalyptic number.

It is an amenable number.

1980921 is a deficient number, since it is larger than the sum of its proper divisors (922119).

1980921 is a wasteful number, since it uses less digits than its factorization.

1980921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1556.

The product of its (nonzero) digits is 1296, while the sum is 30.

The square root of 1980921 is about 1407.4519529988. The cubic root of 1980921 is about 125.5901903505.

Subtracting from 1980921 its sum of digits (30), we obtain a palindrome (1980891).

The spelling of 1980921 in words is "one million, nine hundred eighty thousand, nine hundred twenty-one".