21106051 has 2 divisors, whose sum is σ = 21106052. Its totient is φ = 21106050.

The previous prime is 21106049. The next prime is 21106067. The reversal of 21106051 is 15060112.

It is a happy number.

It is an a-pointer prime, because the next prime (21106067) can be obtained adding 21106051 to its sum of digits (16).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21106051 - 2¹ = 21106049 is a prime.

Together with 21106049, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21103051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10553025 + 10553026.

It is an arithmetic number, because the mean of its divisors is an integer number (10553026).

Almost surely, 2^21106051 is an apocalyptic number.

21106051 is a deficient number, since it is larger than the sum of its proper divisors (1).

21106051 is an equidigital number, since it uses as much as digits as its factorization.

21106051 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 60, while the sum is 16.

The square root of 21106051 is about 4594.1322357982. The cubic root of 21106051 is about 276.3560613198.

Adding to 21106051 its reverse (15060112), we get a palindrome (36166163).

The spelling of 21106051 in words is "twenty-one million, one hundred six thousand, fifty-one".