406392821 has 2 divisors, whose sum is σ = 406392822. Its totient is φ = 406392820.

The previous prime is 406392809. The next prime is 406392841. The reversal of 406392821 is 128293604.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 385690321 + 20702500 = 19639^2 + 4550^2 .

It is a cyclic number.

It is not a de Polignac number, because 406392821 - 2¹⁸ = 406130677 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (406392841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 203196410 + 203196411.

It is an arithmetic number, because the mean of its divisors is an integer number (203196411).

Almost surely, 2^406392821 is an apocalyptic number.

It is an amenable number.

406392821 is a deficient number, since it is larger than the sum of its proper divisors (1).

406392821 is an equidigital number, since it uses as much as digits as its factorization.

406392821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20736, while the sum is 35.

The square root of 406392821 is about 20159.1870123773. The cubic root of 406392821 is about 740.7107980410.

The spelling of 406392821 in words is "four hundred six million, three hundred ninety-two thousand, eight hundred twenty-one".