20004013521 has 6 divisors (see below), whose sum is σ = 28894686210. Its totient is φ = 13336009008.

The previous prime is 20004013517. The next prime is 20004013541. The reversal of 20004013521 is 12531040002.

It can be written as a sum of positive squares in only one way, i.e., 15154841025 + 4849172496 = 123105^2 + 69636^2 .

It is not a de Polignac number, because 20004013521 - 2² = 20004013517 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20004013494 and 20004013503.

It is not an unprimeable number, because it can be changed into a prime (20004013511) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1111334076 + ... + 1111334093.

It is an arithmetic number, because the mean of its divisors is an integer number (4815781035).

Almost surely, 2^20004013521 is an apocalyptic number.

It is an amenable number.

20004013521 is a deficient number, since it is larger than the sum of its proper divisors (8890672689).

20004013521 is a wasteful number, since it uses less digits than its factorization.

20004013521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2222668175 (or 2222668172 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

Adding to 20004013521 its reverse (12531040002), we get a palindrome (32535053523).

The spelling of 20004013521 in words is "twenty billion, four million, thirteen thousand, five hundred twenty-one".