221220427 has 2 divisors, whose sum is σ = 221220428. Its totient is φ = 221220426.

The previous prime is 221220403. The next prime is 221220437. The reversal of 221220427 is 724022122.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 221220427 - 2¹⁹ = 220696139 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221220398 and 221220407.

It is not a weakly prime, because it can be changed into another prime (221220437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110610213 + 110610214.

It is an arithmetic number, because the mean of its divisors is an integer number (110610214).

Almost surely, 2^221220427 is an apocalyptic number.

221220427 is a deficient number, since it is larger than the sum of its proper divisors (1).

221220427 is an equidigital number, since it uses as much as digits as its factorization.

221220427 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 896, while the sum is 22.

The square root of 221220427 is about 14873.4806619029. The cubic root of 221220427 is about 604.7953017395.

Adding to 221220427 its reverse (724022122), we get a palindrome (945242549).

The spelling of 221220427 in words is "two hundred twenty-one million, two hundred twenty thousand, four hundred twenty-seven".