21010120 has 16 divisors (see below), whose sum is σ = 47272860. Its totient is φ = 8404032.

The previous prime is 21010111. The next prime is 21010127. The reversal of 21010120 is 2101012.

It can be written as a sum of positive squares in 2 ways, for example, as 19873764 + 1136356 = 4458^2 + 1066^2 .

It is not an unprimeable number, because it can be changed into a prime (21010127) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 262587 + ... + 262666.

Almost surely, 2^21010120 is an apocalyptic number.

21010120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21010120 is an abundant number, since it is smaller than the sum of its proper divisors (26262740).

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

21010120 is a wasteful number, since it uses less digits than its factorization.

21010120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 525264 (or 525260 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 7.

The square root of 21010120 is about 4583.6797444848. The cubic root of 21010120 is about 275.9367284776.

Adding to 21010120 its reverse (2101012), we get a palindrome (23111132).

The spelling of 21010120 in words is "twenty-one million, ten thousand, one hundred twenty".