21112405667 has 4 divisors (see below), whose sum is σ = 21188624016. Its totient is φ = 21036187320.

The previous prime is 21112405631. The next prime is 21112405669. The reversal of 21112405667 is 76650421112.

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 21112405667 - 2⁶ = 21112405603 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21112405669) 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, 38108759 + ... + 38109312.

It is an arithmetic number, because the mean of its divisors is an integer number (5297156004).

Almost surely, 2^21112405667 is an apocalyptic number.

21112405667 is a deficient number, since it is larger than the sum of its proper divisors (76218349).

21112405667 is an equidigital number, since it uses as much as digits as its factorization.

21112405667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76218348.

The product of its (nonzero) digits is 20160, while the sum is 35.

Adding to 21112405667 its reverse (76650421112), we get a palindrome (97762826779).

The spelling of 21112405667 in words is "twenty-one billion, one hundred twelve million, four hundred five thousand, six hundred sixty-seven".