1213515421553 has 4 divisors (see below), whose sum is σ = 1217116357860. Its totient is φ = 1209914485248.

The previous prime is 1213515421493. The next prime is 1213515421567. The reversal of 1213515421553 is 3551245153121.

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 431868465889 + 781646955664 = 657167^2 + 884108^2 .

It is a cyclic number.

It is not a de Polignac number, because 1213515421553 - 2³⁴ = 1196335552369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1213515421583) 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, 1800467648 + ... + 1800468321.

It is an arithmetic number, because the mean of its divisors is an integer number (304279089465).

Almost surely, 2^{1213515421553} is an apocalyptic number.

It is an amenable number.

1213515421553 is a deficient number, since it is larger than the sum of its proper divisors (3600936307).

1213515421553 is an equidigital number, since it uses as much as digits as its factorization.

1213515421553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3600936306.

The product of its digits is 90000, while the sum is 38.

The spelling of 1213515421553 in words is "one trillion, two hundred thirteen billion, five hundred fifteen million, four hundred twenty-one thousand, five hundred fifty-three".