406443781 has 2 divisors, whose sum is σ = 406443782. Its totient is φ = 406443780.

The previous prime is 406443767. The next prime is 406443799. The reversal of 406443781 is 187344604.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 336135556 + 70308225 = 18334^2 + 8385^2 .

It is a cyclic number.

It is not a de Polignac number, because 406443781 - 2⁵ = 406443749 is a prime.

It is a super-2 number, since 2×406443781² = 330393094227151922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 406443781.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (406443721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 203221890 + 203221891.

It is an arithmetic number, because the mean of its divisors is an integer number (203221891).

Almost surely, 2^406443781 is an apocalyptic number.

It is an amenable number.

406443781 is a deficient number, since it is larger than the sum of its proper divisors (1).

406443781 is an equidigital number, since it uses as much as digits as its factorization.

406443781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64512, while the sum is 37.

The square root of 406443781 is about 20160.4509126160. The cubic root of 406443781 is about 740.7417574499.

The spelling of 406443781 in words is "four hundred six million, four hundred forty-three thousand, seven hundred eighty-one".