40405340021 has 2 divisors, whose sum is σ = 40405340022. Its totient is φ = 40405340020.

The previous prime is 40405339991. The next prime is 40405340033. The reversal of 40405340021 is 12004350404.

40405340021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21570796900 + 18834543121 = 146870^2 + 137239^2 .

It is a cyclic number.

It is not a de Polignac number, because 40405340021 - 2¹⁸ = 40405077877 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (40405340221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20202670010 + 20202670011.

It is an arithmetic number, because the mean of its divisors is an integer number (20202670011).

Almost surely, 2^40405340021 is an apocalyptic number.

It is an amenable number.

40405340021 is a deficient number, since it is larger than the sum of its proper divisors (1).

40405340021 is an equidigital number, since it uses as much as digits as its factorization.

40405340021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1920, while the sum is 23.

Adding to 40405340021 its reverse (12004350404), we get a palindrome (52409690425).

The spelling of 40405340021 in words is "forty billion, four hundred five million, three hundred forty thousand, twenty-one".