40005404123521 has 4 divisors (see below), whose sum is σ = 40042827327700. Its totient is φ = 39967980919344.

The previous prime is 40005404123519. The next prime is 40005404123561. The reversal of 40005404123521 is 12532140450004.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7382572633921 + 32622831489600 = 2717089^2 + 5711640^2 .

It is a cyclic number.

It is not a de Polignac number, because 40005404123521 - 2¹ = 40005404123519 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (40005404123561) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18711600486 + ... + 18711602623.

It is an arithmetic number, because the mean of its divisors is an integer number (10010706831925).

Almost surely, 2^{40005404123521} is an apocalyptic number.

It is an amenable number.

40005404123521 is a deficient number, since it is larger than the sum of its proper divisors (37423204179).

40005404123521 is a wasteful number, since it uses less digits than its factorization.

40005404123521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37423204178.

The product of its (nonzero) digits is 19200, while the sum is 31.

Adding to 40005404123521 its reverse (12532140450004), we get a palindrome (52537544573525).

The spelling of 40005404123521 in words is "forty trillion, five billion, four hundred four million, one hundred twenty-three thousand, five hundred twenty-one".