1663961 has 4 divisors (see below), whose sum is σ = 1791972. Its totient is φ = 1535952.

The previous prime is 1663951. The next prime is 1663967. The reversal of 1663961 is 1693661.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 732736 + 931225 = 856^2 + 965^2 .

It is a cyclic number.

It is not a de Polignac number, because 1663961 - 2¹⁸ = 1401817 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1663967) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 63986 + ... + 64011.

It is an arithmetic number, because the mean of its divisors is an integer number (447993).

2^1663961 is an apocalyptic number.

It is an amenable number.

1663961 is a deficient number, since it is larger than the sum of its proper divisors (128011).

1663961 is a wasteful number, since it uses less digits than its factorization.

1663961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128010.

The product of its digits is 5832, while the sum is 32.

The square root of 1663961 is about 1289.9461229059. The cubic root of 1663961 is about 118.4989169490.

The spelling of 1663961 in words is "one million, six hundred sixty-three thousand, nine hundred sixty-one".