2143240021 has 4 divisors (see below), whose sum is σ = 2308104652. Its totient is φ = 1978375392.

The previous prime is 2143240007. The next prime is 2143240037. The reversal of 2143240021 is 1200423412.

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 320803921 + 1822436100 = 17911^2 + 42690^2 .

It is a cyclic number.

It is not a de Polignac number, because 2143240021 - 2⁹ = 2143239509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2143240051) 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, 82432296 + ... + 82432321.

It is an arithmetic number, because the mean of its divisors is an integer number (577026163).

Almost surely, 2^2143240021 is an apocalyptic number.

It is an amenable number.

2143240021 is a deficient number, since it is larger than the sum of its proper divisors (164864631).

2143240021 is a wasteful number, since it uses less digits than its factorization.

2143240021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164864630.

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 2143240021 is about 46295.1403605173. The cubic root of 2143240021 is about 1289.3087699554.

Adding to 2143240021 its reverse (1200423412), we get a palindrome (3343663433).

The spelling of 2143240021 in words is "two billion, one hundred forty-three million, two hundred forty thousand, twenty-one".