22721261 has 2 divisors, whose sum is σ = 22721262. Its totient is φ = 22721260.

The previous prime is 22721227. The next prime is 22721267. The reversal of 22721261 is 16212722.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12602500 + 10118761 = 3550^2 + 3181^2 .

It is a cyclic number.

It is not a de Polignac number, because 22721261 - 2¹⁰ = 22720237 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (22721267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11360630 + 11360631.

It is an arithmetic number, because the mean of its divisors is an integer number (11360631).

Almost surely, 2^22721261 is an apocalyptic number.

It is an amenable number.

22721261 is a deficient number, since it is larger than the sum of its proper divisors (1).

22721261 is an equidigital number, since it uses as much as digits as its factorization.

22721261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 672, while the sum is 23.

The square root of 22721261 is about 4766.6823892515. The cubic root of 22721261 is about 283.2331898298.

Adding to 22721261 its reverse (16212722), we get a palindrome (38933983).

The spelling of 22721261 in words is "twenty-two million, seven hundred twenty-one thousand, two hundred sixty-one".