405642636 has 36 divisors (see below), whose sum is σ = 1171857232. Its totient is φ = 115897824.

The previous prime is 405642631. The next prime is 405642649. The reversal of 405642636 is 636246504.

405642636 is a `hidden beast` number, since 4 + 0 + 5 + 642 + 6 + 3 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 405642636.

It is not an unprimeable number, because it can be changed into a prime (405642631) 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, 804595 + ... + 805098.

Almost surely, 2^405642636 is an apocalyptic number.

It is an amenable number.

405642636 is an abundant number, since it is smaller than the sum of its proper divisors (766214596).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

405642636 is a wasteful number, since it uses less digits than its factorization.

405642636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1609710 (or 1609705 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 36.

The square root of 405642636 is about 20140.5718886034. The cubic root of 405642636 is about 740.2547430720.

The spelling of 405642636 in words is "four hundred five million, six hundred forty-two thousand, six hundred thirty-six".