1221365801 has 2 divisors, whose sum is σ = 1221365802. Its totient is φ = 1221365800.

The previous prime is 1221365797. The next prime is 1221365909. The reversal of 1221365801 is 1085631221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1079779600 + 141586201 = 32860^2 + 11899^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221365801 - 2² = 1221365797 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221305801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610682900 + 610682901.

It is an arithmetic number, because the mean of its divisors is an integer number (610682901).

Almost surely, 2^1221365801 is an apocalyptic number.

It is an amenable number.

1221365801 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221365801 is an equidigital number, since it uses as much as digits as its factorization.

1221365801 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 1221365801 is about 34948.0443086591. The cubic root of 1221365801 is about 1068.9283243317.

The spelling of 1221365801 in words is "one billion, two hundred twenty-one million, three hundred sixty-five thousand, eight hundred one".