21311212127 has 2 divisors, whose sum is σ = 21311212128. Its totient is φ = 21311212126.

The previous prime is 21311212099. The next prime is 21311212133. The reversal of 21311212127 is 72121211312.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21311212127 - 2¹⁴ = 21311195743 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21311212177) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10655606063 + 10655606064.

It is an arithmetic number, because the mean of its divisors is an integer number (10655606064).

Almost surely, 2^21311212127 is an apocalyptic number.

21311212127 is a deficient number, since it is larger than the sum of its proper divisors (1).

21311212127 is an equidigital number, since it uses as much as digits as its factorization.

21311212127 is an evil number, because the sum of its binary digits is even.

The product of its digits is 336, while the sum is 23.

Adding to 21311212127 its reverse (72121211312), we get a palindrome (93432423439).

The spelling of 21311212127 in words is "twenty-one billion, three hundred eleven million, two hundred twelve thousand, one hundred twenty-seven".