21122112021 has 4 divisors (see below), whose sum is σ = 28162816032. Its totient is φ = 14081408012.

The previous prime is 21122112017. The next prime is 21122112023. The reversal of 21122112021 is 12021122112.

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 21122112021 - 2² = 21122112017 is a prime.

It is a super-2 number, since 2×21122112021² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21122112023) 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, 3520352001 + ... + 3520352006.

It is an arithmetic number, because the mean of its divisors is an integer number (7040704008).

Almost surely, 2^21122112021 is an apocalyptic number.

It is an amenable number.

21122112021 is a deficient number, since it is larger than the sum of its proper divisors (7040704011).

21122112021 is an equidigital number, since it uses as much as digits as its factorization.

21122112021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7040704010.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21122112021 its reverse (12021122112), we get a palindrome (33143234133).

The spelling of 21122112021 in words is "twenty-one billion, one hundred twenty-two million, one hundred twelve thousand, twenty-one".