221220457 has 2 divisors, whose sum is σ = 221220458. Its totient is φ = 221220456.

The previous prime is 221220443. The next prime is 221220469. The reversal of 221220457 is 754022122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 220938496 + 281961 = 14864^2 + 531^2 .

It is a cyclic number.

It is not a de Polignac number, because 221220457 - 2¹⁵ = 221187689 is a prime.

It is not a weakly prime, because it can be changed into another prime (221220427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110610228 + 110610229.

It is an arithmetic number, because the mean of its divisors is an integer number (110610229).

Almost surely, 2^221220457 is an apocalyptic number.

It is an amenable number.

221220457 is a deficient number, since it is larger than the sum of its proper divisors (1).

221220457 is an equidigital number, since it uses as much as digits as its factorization.

221220457 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2240, while the sum is 25.

The square root of 221220457 is about 14873.4816704093. The cubic root of 221220457 is about 604.7953290785.

Adding to 221220457 its reverse (754022122), we get a palindrome (975242579).

The spelling of 221220457 in words is "two hundred twenty-one million, two hundred twenty thousand, four hundred fifty-seven".