1213555150021 has 2 divisors, whose sum is σ = 1213555150022. Its totient is φ = 1213555150020.

The previous prime is 1213555150007. The next prime is 1213555150057. The reversal of 1213555150021 is 1200515553121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1080903312225 + 132651837796 = 1039665^2 + 364214^2 .

It is a cyclic number.

It is not a de Polignac number, because 1213555150021 - 2⁷ = 1213555149893 is a prime.

It is a super-2 number, since 2×1213555150021² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1213555150721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606777575010 + 606777575011.

It is an arithmetic number, because the mean of its divisors is an integer number (606777575011).

Almost surely, 2^{1213555150021} is an apocalyptic number.

It is an amenable number.

1213555150021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1213555150021 is an equidigital number, since it uses as much as digits as its factorization.

1213555150021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7500, while the sum is 31.

The spelling of 1213555150021 in words is "one trillion, two hundred thirteen billion, five hundred fifty-five million, one hundred fifty thousand, twenty-one".