22715221 has 2 divisors, whose sum is σ = 22715222. Its totient is φ = 22715220.

The previous prime is 22715201. The next prime is 22715227. The reversal of 22715221 is 12251722.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19236996 + 3478225 = 4386^2 + 1865^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-22715221 is a prime.

It is equal to p_1431427 and since 22715221 and 1431427 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 22715192 and 22715201.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (22715227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11357610 + 11357611.

It is an arithmetic number, because the mean of its divisors is an integer number (11357611).

Almost surely, 2^22715221 is an apocalyptic number.

It is an amenable number.

22715221 is a deficient number, since it is larger than the sum of its proper divisors (1).

22715221 is an equidigital number, since it uses as much as digits as its factorization.

22715221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 560, while the sum is 22.

The square root of 22715221 is about 4766.0487827969. The cubic root of 22715221 is about 283.2080902827.

Adding to 22715221 its reverse (12251722), we get a palindrome (34966943).

The spelling of 22715221 in words is "twenty-two million, seven hundred fifteen thousand, two hundred twenty-one".