1221262513 has 2 divisors, whose sum is σ = 1221262514. Its totient is φ = 1221262512.

The previous prime is 1221262499. The next prime is 1221262543. The reversal of 1221262513 is 3152621221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1173542049 + 47720464 = 34257^2 + 6908^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221262513 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221262543) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610631256 + 610631257.

It is an arithmetic number, because the mean of its divisors is an integer number (610631257).

Almost surely, 2^1221262513 is an apocalyptic number.

It is an amenable number.

1221262513 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221262513 is an equidigital number, since it uses as much as digits as its factorization.

1221262513 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1440, while the sum is 25.

The square root of 1221262513 is about 34946.5665409350. The cubic root of 1221262513 is about 1068.8981912405.

Adding to 1221262513 its reverse (3152621221), we get a palindrome (4373883734).

The spelling of 1221262513 in words is "one billion, two hundred twenty-one million, two hundred sixty-two thousand, five hundred thirteen".