20617020 has 72 divisors (see below), whose sum is σ = 63895104. Its totient is φ = 5378688.

The previous prime is 20617013. The next prime is 20617027. The reversal of 20617020 is 2071602.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20617013) and next prime (20617027).

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

It is a junction number, because it is equal to n+sod(n) for n = 20616984 and 20617002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20617027) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7242 + ... + 9678.

It is an arithmetic number, because the mean of its divisors is an integer number (887432).

Almost surely, 2^20617020 is an apocalyptic number.

20617020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20617020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31947552).

20617020 is an abundant number, since it is smaller than the sum of its proper divisors (43278084).

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

20617020 is a wasteful number, since it uses less digits than its factorization.

20617020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2499 (or 2494 counting only the distinct ones).

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

The square root of 20617020 is about 4540.5968770636. The cubic root of 20617020 is about 274.2049543672.

Adding to 20617020 its reverse (2071602), we get a palindrome (22688622).

The spelling of 20617020 in words is "twenty million, six hundred seventeen thousand, twenty".