21019020443 has 4 divisors (see below), whose sum is σ = 21033310848. Its totient is φ = 21004730040.

The previous prime is 21019020437. The next prime is 21019020497. The reversal of 21019020443 is 34402091012.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21019020443 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21019029443) 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, 7142996 + ... + 7145937.

It is an arithmetic number, because the mean of its divisors is an integer number (5258327712).

Almost surely, 2^21019020443 is an apocalyptic number.

21019020443 is a deficient number, since it is larger than the sum of its proper divisors (14290405).

21019020443 is a wasteful number, since it uses less digits than its factorization.

21019020443 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14290404.

The product of its (nonzero) digits is 1728, while the sum is 26.

The spelling of 21019020443 in words is "twenty-one billion, nineteen million, twenty thousand, four hundred forty-three".