20816670 has 120 divisors (see below), whose sum is σ = 61913304. Its totient is φ = 4478208.

The previous prime is 20816669. The next prime is 20816689. The reversal of 20816670 is 7661802.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 1224502 + ... + 1224518.

Almost surely, 2^20816670 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20816670, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30956652).

20816670 is an abundant number, since it is smaller than the sum of its proper divisors (41096634).

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

20816670 is an equidigital number, since it uses as much as digits as its factorization.

20816670 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72 (or 34 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 30.

The square root of 20816670 is about 4562.5289040180. The cubic root of 20816670 is about 275.0872230209.

Multiplying 20816670 by its sum of digits (30), we get a square (624500100 = 24990²).

20816670 divided by its sum of digits (30) gives a square (693889 = 833²).

The spelling of 20816670 in words is "twenty million, eight hundred sixteen thousand, six hundred seventy".