1220021717 has 2 divisors, whose sum is σ = 1220021718. Its totient is φ = 1220021716.

The previous prime is 1220021659. The next prime is 1220021767. The reversal of 1220021717 is 7171200221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1217591236 + 2430481 = 34894^2 + 1559^2 .

It is an emirp because it is prime and its reverse (7171200221) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1220021717 - 2⁶ = 1220021653 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1220021692 and 1220021701.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1220021767) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610010858 + 610010859.

It is an arithmetic number, because the mean of its divisors is an integer number (610010859).

Almost surely, 2^1220021717 is an apocalyptic number.

It is an amenable number.

1220021717 is a deficient number, since it is larger than the sum of its proper divisors (1).

1220021717 is an equidigital number, since it uses as much as digits as its factorization.

1220021717 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 392, while the sum is 23.

The square root of 1220021717 is about 34928.8092697132. The cubic root of 1220021717 is about 1068.5360703463.

Adding to 1220021717 its reverse (7171200221), we get a palindrome (8391221938).

The spelling of 1220021717 in words is "one billion, two hundred twenty million, twenty-one thousand, seven hundred seventeen".