1986921 has 12 divisors (see below), whose sum is σ = 2883972. Its totient is φ = 1318176.

The previous prime is 1986913. The next prime is 1986923. The reversal of 1986921 is 1296891.

It can be written as a sum of positive squares in 2 ways, for example, as 632025 + 1354896 = 795^2 + 1164^2 .

It is not a de Polignac number, because 1986921 - 2³ = 1986913 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1986923) 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 11 ways as a sum of consecutive naturals, for example, 2095 + ... + 2891.

It is an arithmetic number, because the mean of its divisors is an integer number (240331).

2^1986921 is an apocalyptic number.

It is an amenable number.

1986921 is a deficient number, since it is larger than the sum of its proper divisors (897051).

1986921 is a wasteful number, since it uses less digits than its factorization.

1986921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1080 (or 1077 counting only the distinct ones).

The product of its digits is 7776, while the sum is 36.

The square root of 1986921 is about 1409.5818528911. The cubic root of 1986921 is about 125.7168623414.

The spelling of 1986921 in words is "one million, nine hundred eighty-six thousand, nine hundred twenty-one".