406765561 has 2 divisors, whose sum is σ = 406765562. Its totient is φ = 406765560.

The previous prime is 406765559. The next prime is 406765591. The reversal of 406765561 is 165567604.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 351337536 + 55428025 = 18744^2 + 7445^2 .

It is a cyclic number.

It is not a de Polignac number, because 406765561 - 2¹ = 406765559 is a prime.

Together with 406765559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (406765591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 203382780 + 203382781.

It is an arithmetic number, because the mean of its divisors is an integer number (203382781).

Almost surely, 2^406765561 is an apocalyptic number.

It is an amenable number.

406765561 is a deficient number, since it is larger than the sum of its proper divisors (1).

406765561 is an equidigital number, since it uses as much as digits as its factorization.

406765561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 151200, while the sum is 40.

The square root of 406765561 is about 20168.4298099778. The cubic root of 406765561 is about 740.9371866989.

The spelling of 406765561 in words is "four hundred six million, seven hundred sixty-five thousand, five hundred sixty-one".