21004212443 has 4 divisors (see below), whose sum is σ = 21240214920. Its totient is φ = 20768209968.

The previous prime is 21004212433. The next prime is 21004212497. The reversal of 21004212443 is 34421240012.

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 21004212443 - 2¹² = 21004208347 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21004212413) 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, 118001105 + ... + 118001282.

It is an arithmetic number, because the mean of its divisors is an integer number (5310053730).

Almost surely, 2^21004212443 is an apocalyptic number.

21004212443 is a deficient number, since it is larger than the sum of its proper divisors (236002477).

21004212443 is an equidigital number, since it uses as much as digits as its factorization.

21004212443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 236002476.

The product of its (nonzero) digits is 1536, while the sum is 23.

Adding to 21004212443 its reverse (34421240012), we get a palindrome (55425452455).

The spelling of 21004212443 in words is "twenty-one billion, four million, two hundred twelve thousand, four hundred forty-three".