21212122051 has 2 divisors, whose sum is σ = 21212122052. Its totient is φ = 21212122050.

The previous prime is 21212122039. The next prime is 21212122067. The reversal of 21212122051 is 15022121212.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21212122051 - 2²⁹ = 20675251139 is a prime.

It is not a weakly prime, because it can be changed into another prime (21212122081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606061025 + 10606061026.

It is an arithmetic number, because the mean of its divisors is an integer number (10606061026).

Almost surely, 2^21212122051 is an apocalyptic number.

21212122051 is a deficient number, since it is larger than the sum of its proper divisors (1).

21212122051 is an equidigital number, since it uses as much as digits as its factorization.

21212122051 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 160, while the sum is 19.

Adding to 21212122051 its reverse (15022121212), we get a palindrome (36234243263).

The spelling of 21212122051 in words is "twenty-one billion, two hundred twelve million, one hundred twenty-two thousand, fifty-one".