405440021009 has 2 divisors, whose sum is σ = 405440021010. Its totient is φ = 405440021008.

The previous prime is 405440020967. The next prime is 405440021011. The reversal of 405440021009 is 900120044504.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 333473910784 + 71966110225 = 577472^2 + 268265^2 .

It is a cyclic number.

It is not a de Polignac number, because 405440021009 - 2⁸ = 405440020753 is a prime.

It is a super-2 number, since 2×405440021009² (a number of 24 digits) contains 22 as substring.

Together with 405440021011, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (405440026009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 202720010504 + 202720010505.

It is an arithmetic number, because the mean of its divisors is an integer number (202720010505).

Almost surely, 2^405440021009 is an apocalyptic number.

It is an amenable number.

405440021009 is a deficient number, since it is larger than the sum of its proper divisors (1).

405440021009 is an equidigital number, since it uses as much as digits as its factorization.

405440021009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5760, while the sum is 29.

The spelling of 405440021009 in words is "four hundred five billion, four hundred forty million, twenty-one thousand, nine".