1662561 has 24 divisors (see below), whose sum is σ = 2545920. Its totient is φ = 1044000.

The previous prime is 1662559. The next prime is 1662571. The reversal of 1662561 is 1652661.

1662561 = 138² + 139² + ... + 196².

It is a happy number.

It is not a de Polignac number, because 1662561 - 2¹ = 1662559 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1662571) 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 23 ways as a sum of consecutive naturals, for example, 16411 + ... + 16511.

It is an arithmetic number, because the mean of its divisors is an integer number (106080).

2^1662561 is an apocalyptic number.

It is an amenable number.

1662561 is a deficient number, since it is larger than the sum of its proper divisors (883359).

1662561 is a wasteful number, since it uses less digits than its factorization.

1662561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197 (or 194 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 1662561 is about 1289.4033503912. The cubic root of 1662561 is about 118.4656739759.

The spelling of 1662561 in words is "one million, six hundred sixty-two thousand, five hundred sixty-one".