1661633 has 4 divisors (see below), whose sum is σ = 1706580. Its totient is φ = 1616688.

The previous prime is 1661629. The next prime is 1661641. The reversal of 1661633 is 3361661.

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 908209 + 753424 = 953^2 + 868^2 .

It is a cyclic number.

It is not a de Polignac number, because 1661633 - 2² = 1661629 is a prime.

It is a super-2 number, since 2×1661633² = 5522048453378, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661623) 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, 22418 + ... + 22491.

It is an arithmetic number, because the mean of its divisors is an integer number (426645).

2^1661633 is an apocalyptic number.

It is an amenable number.

1661633 is a deficient number, since it is larger than the sum of its proper divisors (44947).

1661633 is an equidigital number, since it uses as much as digits as its factorization.

1661633 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44946.

The product of its digits is 1944, while the sum is 26.

The square root of 1661633 is about 1289.0434437985. The cubic root of 1661633 is about 118.4436283474.

The spelling of 1661633 in words is "one million, six hundred sixty-one thousand, six hundred thirty-three".