406645891 has 2 divisors, whose sum is σ = 406645892. Its totient is φ = 406645890.

The previous prime is 406645867. The next prime is 406645907. The reversal of 406645891 is 198546604.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-406645891 is a prime.

It is not a weakly prime, because it can be changed into another prime (406645861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 203322945 + 203322946.

It is an arithmetic number, because the mean of its divisors is an integer number (203322946).

Almost surely, 2^406645891 is an apocalyptic number.

406645891 is a deficient number, since it is larger than the sum of its proper divisors (1).

406645891 is an equidigital number, since it uses as much as digits as its factorization.

406645891 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 207360, while the sum is 43.

The square root of 406645891 is about 20165.4628263276. The cubic root of 406645891 is about 740.8645185919.

The spelling of 406645891 in words is "four hundred six million, six hundred forty-five thousand, eight hundred ninety-one".