405726661 has 2 divisors, whose sum is σ = 405726662. Its totient is φ = 405726660.

The previous prime is 405726649. The next prime is 405726679. The reversal of 405726661 is 166627504.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 372721636 + 33005025 = 19306^2 + 5745^2 .

It is a cyclic number.

It is not a de Polignac number, because 405726661 - 2⁹ = 405726149 is a prime.

It is a super-2 number, since 2×405726661² = 329228246892417842, 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 405726661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (405726631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 202863330 + 202863331.

It is an arithmetic number, because the mean of its divisors is an integer number (202863331).

Almost surely, 2^405726661 is an apocalyptic number.

It is an amenable number.

405726661 is a deficient number, since it is larger than the sum of its proper divisors (1).

405726661 is an equidigital number, since it uses as much as digits as its factorization.

405726661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 60480, while the sum is 37.

The square root of 405726661 is about 20142.6577442005. The cubic root of 405726661 is about 740.3058517779.

The spelling of 405726661 in words is "four hundred five million, seven hundred twenty-six thousand, six hundred sixty-one".