21123203120 has 80 divisors (see below), whose sum is σ = 52301518560. Its totient is φ = 7906209792.

The previous prime is 21123203099. The next prime is 21123203141. The reversal of 21123203120 is 2130232112.

It is an interprime number because it is at equal distance from previous prime (21123203099) and next prime (21123203141).

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (17).

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, 190391 + ... + 280169.

It is an arithmetic number, because the mean of its divisors is an integer number (653768982).

Almost surely, 2^21123203120 is an apocalyptic number.

21123203120 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 21123203120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26150759280).

21123203120 is an abundant number, since it is smaller than the sum of its proper divisors (31178315440).

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

21123203120 is a wasteful number, since it uses less digits than its factorization.

21123203120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89982 (or 89976 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 21123203120 its reverse (2130232112), we get a palindrome (23253435232).

The spelling of 21123203120 in words is "twenty-one billion, one hundred twenty-three million, two hundred three thousand, one hundred twenty".