21155315256413 has 16 divisors (see below), whose sum is σ = 22869888281856. Its totient is φ = 19453209242880.

The previous prime is 21155315256407. The next prime is 21155315256419. The reversal of 21155315256413 is 31465251355112.

It is an interprime number because it is at equal distance from previous prime (21155315256407) and next prime (21155315256419).

It is a cyclic number.

It is not a de Polignac number, because 21155315256413 - 2²⁶ = 21155248147549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21155315256419) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 191706293 + ... + 191816613.

It is an arithmetic number, because the mean of its divisors is an integer number (1429368017616).

Almost surely, 2^{21155315256413} is an apocalyptic number.

It is an amenable number.

21155315256413 is a deficient number, since it is larger than the sum of its proper divisors (1714573025443).

21155315256413 is a wasteful number, since it uses less digits than its factorization.

21155315256413 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166684.

The product of its digits is 540000, while the sum is 44.

The spelling of 21155315256413 in words is "twenty-one trillion, one hundred fifty-five billion, three hundred fifteen million, two hundred fifty-six thousand, four hundred thirteen".