20816847 has 6 divisors (see below), whose sum is σ = 30068792. Its totient is φ = 13877892.

The previous prime is 20816839. The next prime is 20816881. The reversal of 20816847 is 74861802.

It is not a de Polignac number, because 20816847 - 2³ = 20816839 is a prime.

It is a super-2 number, since 2×20816847² = 866682238042818, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20816897) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1156483 + ... + 1156500.

Almost surely, 2^20816847 is an apocalyptic number.

20816847 is a deficient number, since it is larger than the sum of its proper divisors (9251945).

20816847 is a wasteful number, since it uses less digits than its factorization.

20816847 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2312989 (or 2312986 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 20816847 is about 4562.5483011142. The cubic root of 20816847 is about 275.0880026893.

The spelling of 20816847 in words is "twenty million, eight hundred sixteen thousand, eight hundred forty-seven".