1221313201 has 4 divisors (see below), whose sum is σ = 1293155172. Its totient is φ = 1149471232.

The previous prime is 1221313193. The next prime is 1221313213. The reversal of 1221313201 is 1023131221.

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 342250000 + 879063201 = 18500^2 + 29649^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221313201 - 2³ = 1221313193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221353201) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35920960 + ... + 35920993.

It is an arithmetic number, because the mean of its divisors is an integer number (323288793).

Almost surely, 2^1221313201 is an apocalyptic number.

It is an amenable number.

1221313201 is a deficient number, since it is larger than the sum of its proper divisors (71841971).

1221313201 is an equidigital number, since it uses as much as digits as its factorization.

1221313201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71841970.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 1221313201 is about 34947.2917548699. The cubic root of 1221313201 is about 1068.9129790963.

Adding to 1221313201 its reverse (1023131221), we get a palindrome (2244444422).

The spelling of 1221313201 in words is "one billion, two hundred twenty-one million, three hundred thirteen thousand, two hundred one".