20985408 has 42 divisors (see below), whose sum is σ = 60152534. Its totient is φ = 6994944.

The previous prime is 20985389. The next prime is 20985409. The reversal of 20985408 is 80458902.

20985408 is a `hidden beast` number, since 20 + 98 + 540 + 8 = 666.

It can be written as a sum of positive squares in only one way, i.e., 20358144 + 627264 = 4512^2 + 792^2 .

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

It is not an unprimeable number, because it can be changed into a prime (20985409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 17641 + ... + 18792.

Almost surely, 2^20985408 is an apocalyptic number.

It is an amenable number.

20985408 is an abundant number, since it is smaller than the sum of its proper divisors (39167126).

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

20985408 is a wasteful number, since it uses less digits than its factorization.

20985408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36451 (or 36438 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The square root of 20985408 is about 4580.9833005590. The cubic root of 20985408 is about 275.8285008925.

The spelling of 20985408 in words is "twenty million, nine hundred eighty-five thousand, four hundred eight".