20211620 has 96 divisors (see below), whose sum is σ = 51480576. Its totient is φ = 6566400.

The previous prime is 20211619. The next prime is 20211643. The reversal of 20211620 is 2611202.

It is a junction number, because it is equal to n+sod(n) for n = 20211595 and 20211604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 105725 + ... + 105915.

It is an arithmetic number, because the mean of its divisors is an integer number (536256).

Almost surely, 2^20211620 is an apocalyptic number.

20211620 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 20211620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25740288).

20211620 is an abundant number, since it is smaller than the sum of its proper divisors (31268956).

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

20211620 is a wasteful number, since it uses less digits than its factorization.

20211620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 261 (or 259 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 20211620 is about 4495.7335330288. The cubic root of 20211620 is about 272.3957798011.

Adding to 20211620 its reverse (2611202), we get a palindrome (22822822).

The spelling of 20211620 in words is "twenty million, two hundred eleven thousand, six hundred twenty".