20515555142321 has 16 divisors (see below), whose sum is σ = 21732729138000. Its totient is φ = 19299535976448.

The previous prime is 20515555142281. The next prime is 20515555142323. The reversal of 20515555142321 is 12324155551502.

It can be written as a sum of positive squares in 8 ways, for example, as 996513045025 + 19519042097296 = 998255^2 + 4418036^2 .

It is not a de Polignac number, because 20515555142321 - 2²² = 20515550948017 is a prime.

It is a super-2 number, since 2×20515555142321² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20515555142323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 439762205 + ... + 439808853.

It is an arithmetic number, because the mean of its divisors is an integer number (1358295571125).

Almost surely, 2^{20515555142321} is an apocalyptic number.

It is an amenable number.

20515555142321 is a deficient number, since it is larger than the sum of its proper divisors (1217173995679).

20515555142321 is a wasteful number, since it uses less digits than its factorization.

20515555142321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58468.

The product of its (nonzero) digits is 300000, while the sum is 41.

The spelling of 20515555142321 in words is "twenty trillion, five hundred fifteen billion, five hundred fifty-five million, one hundred forty-two thousand, three hundred twenty-one".