405556561 has 16 divisors (see below), whose sum is σ = 434960640. Its totient is φ = 377435520.

The previous prime is 405556507. The next prime is 405556589. The reversal of 405556561 is 165655504.

It is a cyclic number.

It is not a de Polignac number, because 405556561 - 2⁷ = 405556433 is a prime.

It is a super-2 number, since 2×405556561² = 328952248340293442, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 405556561.

It is not an unprimeable number, because it can be changed into a prime (405556061) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 89101 + ... + 93541.

It is an arithmetic number, because the mean of its divisors is an integer number (27185040).

Almost surely, 2^405556561 is an apocalyptic number.

It is an amenable number.

405556561 is a deficient number, since it is larger than the sum of its proper divisors (29404079).

405556561 is a wasteful number, since it uses less digits than its factorization.

405556561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4584.

The product of its (nonzero) digits is 90000, while the sum is 37.

The square root of 405556561 is about 20138.4349193278. The cubic root of 405556561 is about 740.2023801227.

The spelling of 405556561 in words is "four hundred five million, five hundred fifty-six thousand, five hundred sixty-one".