405942561 has 12 divisors (see below), whose sum is σ = 594394788. Its totient is φ = 266920704.

The previous prime is 405942547. The next prime is 405942623. The reversal of 405942561 is 165249504.

405942561 is a `hidden beast` number, since 4 + 0 + 5 + 94 + 2 + 561 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 284259600 + 121682961 = 16860^2 + 11031^2 .

It is not a de Polignac number, because 405942561 - 2¹⁰ = 405941537 is a prime.

It is not an unprimeable number, because it can be changed into a prime (405942521) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 308280 + ... + 309593.

It is an arithmetic number, because the mean of its divisors is an integer number (49532899).

Almost surely, 2^405942561 is an apocalyptic number.

It is an amenable number.

405942561 is a deficient number, since it is larger than the sum of its proper divisors (188452227).

405942561 is a wasteful number, since it uses less digits than its factorization.

405942561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 617952 (or 617949 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

The square root of 405942561 is about 20148.0163043412. The cubic root of 405942561 is about 740.4371418858.

The spelling of 405942561 in words is "four hundred five million, nine hundred forty-two thousand, five hundred sixty-one".