1661233143 has 4 divisors (see below), whose sum is σ = 2214977528. Its totient is φ = 1107488760.

The previous prime is 1661233127. The next prime is 1661233151. The reversal of 1661233143 is 3413321661.

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

It is not a de Polignac number, because 1661233143 - 2⁴ = 1661233127 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1661233143.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661233103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 276872188 + ... + 276872193.

It is an arithmetic number, because the mean of its divisors is an integer number (553744382).

Almost surely, 2^1661233143 is an apocalyptic number.

1661233143 is a deficient number, since it is larger than the sum of its proper divisors (553744385).

1661233143 is an equidigital number, since it uses as much as digits as its factorization.

1661233143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 553744384.

The product of its digits is 7776, while the sum is 30.

The square root of 1661233143 is about 40758.2279178082. The cubic root of 1661233143 is about 1184.3412678813.

The spelling of 1661233143 in words is "one billion, six hundred sixty-one million, two hundred thirty-three thousand, one hundred forty-three".