406821647 has 2 divisors, whose sum is σ = 406821648. Its totient is φ = 406821646.

The previous prime is 406821617. The next prime is 406821671. The reversal of 406821647 is 746128604.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 406821647 - 2⁸ = 406821391 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 406821647.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (406821617) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 203410823 + 203410824.

It is an arithmetic number, because the mean of its divisors is an integer number (203410824).

Almost surely, 2^406821647 is an apocalyptic number.

406821647 is a deficient number, since it is larger than the sum of its proper divisors (1).

406821647 is an equidigital number, since it uses as much as digits as its factorization.

406821647 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64512, while the sum is 38.

The square root of 406821647 is about 20169.8202024708. The cubic root of 406821647 is about 740.9712393139.

The spelling of 406821647 in words is "four hundred six million, eight hundred twenty-one thousand, six hundred forty-seven".