1221445450649 has 4 divisors (see below), whose sum is σ = 1226687706036. Its totient is φ = 1216203195264.

The previous prime is 1221445450639. The next prime is 1221445450661. The reversal of 1221445450649 is 9460545441221.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 827086570249 + 394358880400 = 909443^2 + 627980^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221445450649 is a prime.

It is a super-2 number, since 2×1221445450649² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221445450639) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2621127344 + ... + 2621127809.

It is an arithmetic number, because the mean of its divisors is an integer number (306671926509).

Almost surely, 2^{1221445450649} is an apocalyptic number.

It is an amenable number.

1221445450649 is a deficient number, since it is larger than the sum of its proper divisors (5242255387).

1221445450649 is an equidigital number, since it uses as much as digits as its factorization.

1221445450649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5242255386.

The product of its (nonzero) digits is 1382400, while the sum is 47.

The spelling of 1221445450649 in words is "one trillion, two hundred twenty-one billion, four hundred forty-five million, four hundred fifty thousand, six hundred forty-nine".