21145504120 has 128 divisors (see below), whose sum is σ = 52152488640. Its totient is φ = 7669002240.

The previous prime is 21145504057. The next prime is 21145504129. The reversal of 21145504120 is 2140554112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21145504129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10513915 + ... + 10515925.

Almost surely, 2^21145504120 is an apocalyptic number.

21145504120 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 21145504120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26076244320).

21145504120 is an abundant number, since it is smaller than the sum of its proper divisors (31006984520).

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

21145504120 is a wasteful number, since it uses less digits than its factorization.

21145504120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2385 (or 2381 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 25.

The spelling of 21145504120 in words is "twenty-one billion, one hundred forty-five million, five hundred four thousand, one hundred twenty".