21005424415145 has 8 divisors (see below), whose sum is σ = 25268138907720. Its totient is φ = 16763253125760.

The previous prime is 21005424415081. The next prime is 21005424415193. The reversal of 21005424415145 is 54151442450012.

It can be written as a sum of positive squares in 4 ways, for example, as 621978286336 + 20383446128809 = 788656^2 + 4514803^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21005424415145 - 2⁶ = 21005424415081 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21005424415099 and 21005424415108.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5135798546 + ... + 5135802635.

It is an arithmetic number, because the mean of its divisors is an integer number (3158517363465).

Almost surely, 2^{21005424415145} is an apocalyptic number.

It is an amenable number.

21005424415145 is a deficient number, since it is larger than the sum of its proper divisors (4262714492575).

21005424415145 is a wasteful number, since it uses less digits than its factorization.

21005424415145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10271601595.

The product of its (nonzero) digits is 128000, while the sum is 38.

Adding to 21005424415145 its reverse (54151442450012), we get a palindrome (75156866865157).

The spelling of 21005424415145 in words is "twenty-one trillion, five billion, four hundred twenty-four million, four hundred fifteen thousand, one hundred forty-five".