1221220055245 has 4 divisors (see below), whose sum is σ = 1465464066300. Its totient is φ = 976976044192.

The previous prime is 1221220055239. The next prime is 1221220055291. The reversal of 1221220055245 is 5425500221221.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 172027516644 + 1049192538601 = 414762^2 + 1024301^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221220055245 - 2¹³ = 1221220047053 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 122122005520 + ... + 122122005529.

It is an arithmetic number, because the mean of its divisors is an integer number (366366016575).

Almost surely, 2^{1221220055245} is an apocalyptic number.

It is an amenable number.

1221220055245 is a deficient number, since it is larger than the sum of its proper divisors (244244011055).

1221220055245 is an equidigital number, since it uses as much as digits as its factorization.

1221220055245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 244244011054.

The product of its (nonzero) digits is 16000, while the sum is 31.

Adding to 1221220055245 its reverse (5425500221221), we get a palindrome (6646720276466).

The spelling of 1221220055245 in words is "one trillion, two hundred twenty-one billion, two hundred twenty million, fifty-five thousand, two hundred forty-five".