21111111897 has 4 divisors (see below), whose sum is σ = 28148149200. Its totient is φ = 14074074596.

The previous prime is 21111111883. The next prime is 21111111899. The reversal of 21111111897 is 79811111112.

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 21111111897 - 2⁴ = 21111111881 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21111111899) 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, 3518518647 + ... + 3518518652.

It is an arithmetic number, because the mean of its divisors is an integer number (7037037300).

Almost surely, 2^21111111897 is an apocalyptic number.

It is an amenable number.

21111111897 is a deficient number, since it is larger than the sum of its proper divisors (7037037303).

21111111897 is an equidigital number, since it uses as much as digits as its factorization.

21111111897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7037037302.

The product of its digits is 1008, while the sum is 33.

The spelling of 21111111897 in words is "twenty-one billion, one hundred eleven million, one hundred eleven thousand, eight hundred ninety-seven".