1986561 has 12 divisors (see below), whose sum is σ = 2898688. Its totient is φ = 1310904.

The previous prime is 1986553. The next prime is 1986577. The reversal of 1986561 is 1656891.

1986561 is a `hidden beast` number, since 1 + 98 + 6 + 561 = 666.

It is not a de Polignac number, because 1986561 - 2³ = 1986553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1986541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 145 + ... + 1998.

It is a Proth number, since it is equal to 485 ⋅ 2¹² + 1 and 485 < 2¹².

2^1986561 is an apocalyptic number.

It is an amenable number.

1986561 is a deficient number, since it is larger than the sum of its proper divisors (912127).

1986561 is a wasteful number, since it uses less digits than its factorization.

1986561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2252 (or 2249 counting only the distinct ones).

The product of its digits is 12960, while the sum is 36.

The square root of 1986561 is about 1409.4541496622. The cubic root of 1986561 is about 125.7092692189.

The spelling of 1986561 in words is "one million, nine hundred eighty-six thousand, five hundred sixty-one".