20211516 has 72 divisors (see below), whose sum is σ = 57941520. Its totient is φ = 5889024.

The previous prime is 20211493. The next prime is 20211517. The reversal of 20211516 is 61511202.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20211517) 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, 7756 + ... + 10028.

Almost surely, 2^20211516 is an apocalyptic number.

20211516 is a gapful number since it is divisible by the number (26) 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 20211516, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28970760).

20211516 is an abundant number, since it is smaller than the sum of its proper divisors (37730004).

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

20211516 is a wasteful number, since it uses less digits than its factorization.

20211516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2315 (or 2310 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

The square root of 20211516 is about 4495.7219664921. The cubic root of 20211516 is about 272.3953125912.

Adding to 20211516 its reverse (61511202), we get a palindrome (81722718).

It can be divided in two parts, 202 and 11516, that multiplied together give a palindrome (2326232).

The spelling of 20211516 in words is "twenty million, two hundred eleven thousand, five hundred sixteen".