21004918043 has 4 divisors (see below), whose sum is σ = 21021291048. Its totient is φ = 20988545040.

The previous prime is 21004918027. The next prime is 21004918073. The reversal of 21004918043 is 34081940012.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21004918043 - 2⁴ = 21004918027 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21004918073) 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, 8184578 + ... + 8187143.

It is an arithmetic number, because the mean of its divisors is an integer number (5255322762).

Almost surely, 2^21004918043 is an apocalyptic number.

21004918043 is a deficient number, since it is larger than the sum of its proper divisors (16373005).

21004918043 is a wasteful number, since it uses less digits than its factorization.

21004918043 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16373004.

The product of its (nonzero) digits is 6912, while the sum is 32.

The spelling of 21004918043 in words is "twenty-one billion, four million, nine hundred eighteen thousand, forty-three".