1215445221421 has 2 divisors, whose sum is σ = 1215445221422. Its totient is φ = 1215445221420.

The previous prime is 1215445221401. The next prime is 1215445221443. The reversal of 1215445221421 is 1241225445121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 996103802500 + 219341418921 = 998050^2 + 468339^2 .

It is an emirp because it is prime and its reverse (1241225445121) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1215445221421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1215445221401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 607722610710 + 607722610711.

It is an arithmetic number, because the mean of its divisors is an integer number (607722610711).

Almost surely, 2^{1215445221421} is an apocalyptic number.

It is an amenable number.

1215445221421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1215445221421 is an equidigital number, since it uses as much as digits as its factorization.

1215445221421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25600, while the sum is 34.

The spelling of 1215445221421 in words is "one trillion, two hundred fifteen billion, four hundred forty-five million, two hundred twenty-one thousand, four hundred twenty-one".