21221402051 has 2 divisors, whose sum is σ = 21221402052. Its totient is φ = 21221402050.

The previous prime is 21221402021. The next prime is 21221402053. The reversal of 21221402051 is 15020412212.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21221402051 is a prime.

Together with 21221402053, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21221402053) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610701025 + 10610701026.

It is an arithmetic number, because the mean of its divisors is an integer number (10610701026).

Almost surely, 2^21221402051 is an apocalyptic number.

21221402051 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221402051 is an equidigital number, since it uses as much as digits as its factorization.

21221402051 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 320, while the sum is 20.

Adding to 21221402051 its reverse (15020412212), we get a palindrome (36241814263).

The spelling of 21221402051 in words is "twenty-one billion, two hundred twenty-one million, four hundred two thousand, fifty-one".