21181211151 has 4 divisors (see below), whose sum is σ = 28241614872. Its totient is φ = 14120807432.

The previous prime is 21181211147. The next prime is 21181211167. The reversal of 21181211151 is 15111218112.

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 21181211151 - 2² = 21181211147 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21181211171) 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, 3530201856 + ... + 3530201861.

It is an arithmetic number, because the mean of its divisors is an integer number (7060403718).

Almost surely, 2^21181211151 is an apocalyptic number.

21181211151 is a deficient number, since it is larger than the sum of its proper divisors (7060403721).

21181211151 is an equidigital number, since it uses as much as digits as its factorization.

21181211151 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7060403720.

The product of its digits is 160, while the sum is 24.

Adding to 21181211151 its reverse (15111218112), we get a palindrome (36292429263).

The spelling of 21181211151 in words is "twenty-one billion, one hundred eighty-one million, two hundred eleven thousand, one hundred fifty-one".