21020120 has 96 divisors (see below), whose sum is σ = 53721360. Its totient is φ = 7392000.

The previous prime is 21020119. The next prime is 21020159. The reversal of 21020120 is 2102012.

It is a Harshad number since it is a multiple of its sum of digits (8).

It is a junction number, because it is equal to n+sod(n) for n = 21020098 and 21020107.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 208070 + ... + 208170.

Almost surely, 2^21020120 is an apocalyptic number.

21020120 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 21020120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26860680).

21020120 is an abundant number, since it is smaller than the sum of its proper divisors (32701240).

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

21020120 is a wasteful number, since it uses less digits than its factorization.

21020120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 177 (or 162 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 8.

The square root of 21020120 is about 4584.7704413634. The cubic root of 21020120 is about 275.9804999175.

Adding to 21020120 its reverse (2102012), we get a palindrome (23122132).

The spelling of 21020120 in words is "twenty-one million, twenty thousand, one hundred twenty".