21434011021 has 4 divisors (see below), whose sum is σ = 21434375200. Its totient is φ = 21433646844.

The previous prime is 21434011019. The next prime is 21434011033. The reversal of 21434011021 is 12011043412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21434011021 - 2¹ = 21434011019 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21434011021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21434611021) 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, 71361 + ... + 218998.

It is an arithmetic number, because the mean of its divisors is an integer number (5358593800).

Almost surely, 2^21434011021 is an apocalyptic number.

It is an amenable number.

21434011021 is a deficient number, since it is larger than the sum of its proper divisors (364179).

21434011021 is an equidigital number, since it uses as much as digits as its factorization.

21434011021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 364178.

The product of its (nonzero) digits is 192, while the sum is 19.

Adding to 21434011021 its reverse (12011043412), we get a palindrome (33445054433).

The spelling of 21434011021 in words is "twenty-one billion, four hundred thirty-four million, eleven thousand, twenty-one".