636539945 has 8 divisors (see below), whose sum is σ = 764484936. Its totient is φ = 508807296.

The previous prime is 636539861. The next prime is 636539963. The reversal of 636539945 is 549935636.

It can be written as a sum of positive squares in 4 ways, for example, as 9388096 + 627151849 = 3064^2 + 25043^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 636539945 - 2¹⁴ = 636523561 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 636539893 and 636539902.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 46412 + ... + 58541.

It is an arithmetic number, because the mean of its divisors is an integer number (95560617).

Almost surely, 2^636539945 is an apocalyptic number.

It is an amenable number.

636539945 is a deficient number, since it is larger than the sum of its proper divisors (127944991).

636539945 is a wasteful number, since it uses less digits than its factorization.

636539945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106171.

The product of its digits is 2624400, while the sum is 50.

The square root of 636539945 is about 25229.7432606834. The cubic root of 636539945 is about 860.2180558477.

The spelling of 636539945 in words is "six hundred thirty-six million, five hundred thirty-nine thousand, nine hundred forty-five".