20720106 has 48 divisors (see below), whose sum is σ = 49297248. Its totient is φ = 6237600.

The previous prime is 20720087. The next prime is 20720107. The reversal of 20720106 is 60102702.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20720107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 44716 + ... + 45176.

It is an arithmetic number, because the mean of its divisors is an integer number (1027026).

Almost surely, 2^20720106 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20720106, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24648624).

20720106 is an abundant number, since it is smaller than the sum of its proper divisors (28577142).

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

20720106 is a wasteful number, since it uses less digits than its factorization.

20720106 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 707 (or 704 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 20720106 is about 4551.9343141131. The cubic root of 20720106 is about 274.6612070295.

Adding to 20720106 its reverse (60102702), we get a palindrome (80822808).

The spelling of 20720106 in words is "twenty million, seven hundred twenty thousand, one hundred six".