21001233120 has 96 divisors (see below), whose sum is σ = 75604451328. Its totient is φ = 4800281088.

The previous prime is 21001233091. The next prime is 21001233133. The reversal of 21001233120 is 2133210012.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21001233120.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3121824 + ... + 3128543.

It is an arithmetic number, because the mean of its divisors is an integer number (787546368).

Almost surely, 2^21001233120 is an apocalyptic number.

21001233120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001233120 is an abundant number, since it is smaller than the sum of its proper divisors (54603218208).

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

21001233120 is a wasteful number, since it uses less digits than its factorization.

21001233120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6250392 (or 6250384 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

Adding to 21001233120 its reverse (2133210012), we get a palindrome (23134443132).

The spelling of 21001233120 in words is "twenty-one billion, one million, two hundred thirty-three thousand, one hundred twenty".