405328921 has 2 divisors, whose sum is σ = 405328922. Its totient is φ = 405328920.

The previous prime is 405328883. The next prime is 405328927. The reversal of 405328921 is 129823504.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 273538521 + 131790400 = 16539^2 + 11480^2 .

It is a cyclic number.

It is not a de Polignac number, because 405328921 - 2¹⁵ = 405296153 is a prime.

It is not a weakly prime, because it can be changed into another prime (405328927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 202664460 + 202664461.

It is an arithmetic number, because the mean of its divisors is an integer number (202664461).

Almost surely, 2^405328921 is an apocalyptic number.

It is an amenable number.

405328921 is a deficient number, since it is larger than the sum of its proper divisors (1).

405328921 is an equidigital number, since it uses as much as digits as its factorization.

405328921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17280, while the sum is 34.

The square root of 405328921 is about 20132.7822468729. The cubic root of 405328921 is about 740.0638616666.

The spelling of 405328921 in words is "four hundred five million, three hundred twenty-eight thousand, nine hundred twenty-one".