1221503221993 has 2 divisors, whose sum is σ = 1221503221994. Its totient is φ = 1221503221992.

The previous prime is 1221503221969. The next prime is 1221503222119. The reversal of 1221503221993 is 3991223051221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 937571968089 + 283931253904 = 968283^2 + 532852^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221503221993 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221500221993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610751610996 + 610751610997.

It is an arithmetic number, because the mean of its divisors is an integer number (610751610997).

Almost surely, 2^{1221503221993} is an apocalyptic number.

It is an amenable number.

1221503221993 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221503221993 is an equidigital number, since it uses as much as digits as its factorization.

1221503221993 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 58320, while the sum is 40.

The spelling of 1221503221993 in words is "one trillion, two hundred twenty-one billion, five hundred three million, two hundred twenty-one thousand, nine hundred ninety-three".