21042042343 has 16 divisors (see below), whose sum is σ = 24885504000. Its totient is φ = 17408355552.

The previous prime is 21042042337. The next prime is 21042042367. The reversal of 21042042343 is 34324024012.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-21042042343 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21042042313) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 666448 + ... + 697306.

It is an arithmetic number, because the mean of its divisors is an integer number (1555344000).

Almost surely, 2^21042042343 is an apocalyptic number.

21042042343 is a deficient number, since it is larger than the sum of its proper divisors (3843461657).

21042042343 is a wasteful number, since it uses less digits than its factorization.

21042042343 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34254.

The product of its (nonzero) digits is 4608, while the sum is 25.

Adding to 21042042343 its reverse (34324024012), we get a palindrome (55366066355).

The spelling of 21042042343 in words is "twenty-one billion, forty-two million, forty-two thousand, three hundred forty-three".