21122247 has 4 divisors (see below), whose sum is σ = 28163000. Its totient is φ = 14081496.

The previous prime is 21122221. The next prime is 21122251. The reversal of 21122247 is 74222112.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21122247 - 2⁶ = 21122183 is a prime.

It is a super-2 number, since 2×21122247² = 892298636658018, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21122267) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3520372 + ... + 3520377.

It is an arithmetic number, because the mean of its divisors is an integer number (7040750).

Almost surely, 2^21122247 is an apocalyptic number.

21122247 is a deficient number, since it is larger than the sum of its proper divisors (7040753).

21122247 is an equidigital number, since it uses as much as digits as its factorization.

21122247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7040752.

The product of its digits is 448, while the sum is 21.

The square root of 21122247 is about 4595.8945810364. The cubic root of 21122247 is about 276.4267317070.

Adding to 21122247 its reverse (74222112), we get a palindrome (95344359).

The spelling of 21122247 in words is "twenty-one million, one hundred twenty-two thousand, two hundred forty-seven".