21012213441 has 4 divisors (see below), whose sum is σ = 28016284592. Its totient is φ = 14008142292.

The previous prime is 21012213403. The next prime is 21012213473. The reversal of 21012213441 is 14431221012.

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 not a de Polignac number, because 21012213441 - 2⁶ = 21012213377 is a prime.

It is a super-2 number, since 2×21012213441² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21012213841) 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, 3502035571 + ... + 3502035576.

It is an arithmetic number, because the mean of its divisors is an integer number (7004071148).

Almost surely, 2^21012213441 is an apocalyptic number.

It is an amenable number.

21012213441 is a deficient number, since it is larger than the sum of its proper divisors (7004071151).

21012213441 is an equidigital number, since it uses as much as digits as its factorization.

21012213441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7004071150.

The product of its (nonzero) digits is 384, while the sum is 21.

Adding to 21012213441 its reverse (14431221012), we get a palindrome (35443434453).

The spelling of 21012213441 in words is "twenty-one billion, twelve million, two hundred thirteen thousand, four hundred forty-one".