1216379453281 has 4 divisors (see below), whose sum is σ = 1216382194692. Its totient is φ = 1216376711872.

The previous prime is 1216379453239. The next prime is 1216379453287. The reversal of 1216379453281 is 1823549736121.

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 364526137600 + 851853315681 = 603760^2 + 922959^2 .

It is a cyclic number.

It is not a de Polignac number, because 1216379453281 - 2²⁷ = 1216245235553 is a prime.

It is a super-2 number, since 2×1216379453281² (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 (1216379453287) 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, 535516 + ... + 1649101.

It is an arithmetic number, because the mean of its divisors is an integer number (304095548673).

Almost surely, 2^{1216379453281} is an apocalyptic number.

It is an amenable number.

1216379453281 is a deficient number, since it is larger than the sum of its proper divisors (2741411).

1216379453281 is an equidigital number, since it uses as much as digits as its factorization.

1216379453281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2741410.

The product of its digits is 2177280, while the sum is 52.

The spelling of 1216379453281 in words is "one trillion, two hundred sixteen billion, three hundred seventy-nine million, four hundred fifty-three thousand, two hundred eighty-one".