1221724017 has 6 divisors (see below), whose sum is σ = 1764712482. Its totient is φ = 814482672.

The previous prime is 1221724013. The next prime is 1221724039. The reversal of 1221724017 is 7104271221.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 1178480241 + 43243776 = 34329^2 + 6576^2 .

It is not a de Polignac number, because 1221724017 - 2² = 1221724013 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1221724013) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 67873548 + ... + 67873565.

It is an arithmetic number, because the mean of its divisors is an integer number (294118747).

Almost surely, 2^1221724017 is an apocalyptic number.

It is an amenable number.

1221724017 is a deficient number, since it is larger than the sum of its proper divisors (542988465).

1221724017 is a wasteful number, since it uses less digits than its factorization.

1221724017 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135747119 (or 135747116 counting only the distinct ones).

The product of its (nonzero) digits is 1568, while the sum is 27.

The square root of 1221724017 is about 34953.1689121316. The cubic root of 1221724017 is about 1069.0328165867.

Adding to 1221724017 its reverse (7104271221), we get a palindrome (8325995238).

The spelling of 1221724017 in words is "one billion, two hundred twenty-one million, seven hundred twenty-four thousand, seventeen".