20215445510021 has 2 divisors, whose sum is σ = 20215445510022. Its totient is φ = 20215445510020.

The previous prime is 20215445510011. The next prime is 20215445510093. The reversal of 20215445510021 is 12001554451202.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18527041533025 + 1688403976996 = 4304305^2 + 1299386^2 .

It is a cyclic number.

It is not a de Polignac number, because 20215445510021 - 2²² = 20215441315717 is a prime.

It is a super-2 number, since 2×20215445510021² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20215445510021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20215445510011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10107722755010 + 10107722755011.

It is an arithmetic number, because the mean of its divisors is an integer number (10107722755011).

Almost surely, 2^{20215445510021} is an apocalyptic number.

It is an amenable number.

20215445510021 is a deficient number, since it is larger than the sum of its proper divisors (1).

20215445510021 is an equidigital number, since it uses as much as digits as its factorization.

20215445510021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16000, while the sum is 32.

Adding to 20215445510021 its reverse (12001554451202), we get a palindrome (32216999961223).

The spelling of 20215445510021 in words is "twenty trillion, two hundred fifteen billion, four hundred forty-five million, five hundred ten thousand, twenty-one".