21223051 has 2 divisors, whose sum is σ = 21223052. Its totient is φ = 21223050.

The previous prime is 21223009. The next prime is 21223061. The reversal of 21223051 is 15032212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21223051 - 2⁷ = 21222923 is a prime.

It is equal to p_1343131 and since 21223051 and 1343131 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (21223061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10611525 + 10611526.

It is an arithmetic number, because the mean of its divisors is an integer number (10611526).

Almost surely, 2^21223051 is an apocalyptic number.

21223051 is a deficient number, since it is larger than the sum of its proper divisors (1).

21223051 is an equidigital number, since it uses as much as digits as its factorization.

21223051 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21223051 is about 4606.8482718666. The cubic root of 21223051 is about 276.8657744821.

Adding to 21223051 its reverse (15032212), we get a palindrome (36255263).

The spelling of 21223051 in words is "twenty-one million, two hundred twenty-three thousand, fifty-one".