21001120120 has 32 divisors (see below), whose sum is σ = 47388726000. Its totient is φ = 8376233728.

The previous prime is 21001120103. The next prime is 21001120123. The reversal of 21001120120 is 2102110012.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 21001120097 and 21001120106.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001120123) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 742645 + ... + 770404.

Almost surely, 2^21001120120 is an apocalyptic number.

21001120120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001120120 is an abundant number, since it is smaller than the sum of its proper divisors (26387605880).

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

21001120120 is a wasteful number, since it uses less digits than its factorization.

21001120120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1513407 (or 1513403 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21001120120 its reverse (2102110012), we get a palindrome (23103230132).

The spelling of 21001120120 in words is "twenty-one billion, one million, one hundred twenty thousand, one hundred twenty".