20985347 has 4 divisors (see below), whose sum is σ = 21053136. Its totient is φ = 20917560.

The previous prime is 20985337. The next prime is 20985373. The reversal of 20985347 is 74358902.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 74358902 = 2 ⋅37179451.

It is a cyclic number.

It is not a de Polignac number, because 20985347 - 2²⁴ = 4208131 is a prime.

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 20985347.

It is not an unprimeable number, because it can be changed into a prime (20985337) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33428 + ... + 34049.

It is an arithmetic number, because the mean of its divisors is an integer number (5263284).

Almost surely, 2^20985347 is an apocalyptic number.

20985347 is a deficient number, since it is larger than the sum of its proper divisors (67789).

20985347 is an equidigital number, since it uses as much as digits as its factorization.

20985347 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67788.

The product of its (nonzero) digits is 60480, while the sum is 38.

The square root of 20985347 is about 4580.9766425949. The cubic root of 20985347 is about 275.8282336345.

The spelling of 20985347 in words is "twenty million, nine hundred eighty-five thousand, three hundred forty-seven".