21225277 has 2 divisors, whose sum is σ = 21225278. Its totient is φ = 21225276.

The previous prime is 21225263. The next prime is 21225287. The reversal of 21225277 is 77252212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10850436 + 10374841 = 3294^2 + 3221^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21225277 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21225287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10612638 + 10612639.

It is an arithmetic number, because the mean of its divisors is an integer number (10612639).

Almost surely, 2^21225277 is an apocalyptic number.

It is an amenable number.

21225277 is a deficient number, since it is larger than the sum of its proper divisors (1).

21225277 is an equidigital number, since it uses as much as digits as its factorization.

21225277 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3920, while the sum is 28.

The square root of 21225277 is about 4607.0898623752. The cubic root of 21225277 is about 276.8754539209.

Adding to 21225277 its reverse (77252212), we get a palindrome (98477489).

The spelling of 21225277 in words is "twenty-one million, two hundred twenty-five thousand, two hundred seventy-seven".