21033123012 has 48 divisors (see below), whose sum is σ = 59487624000. Its totient is φ = 6373673280.

The previous prime is 21033123011. The next prime is 21033123031. The reversal of 21033123012 is 21032133012.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21033123011) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8851137 + ... + 8853512.

It is an arithmetic number, because the mean of its divisors is an integer number (1239325500).

Almost surely, 2^21033123012 is an apocalyptic number.

21033123012 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21033123012 is an abundant number, since it is smaller than the sum of its proper divisors (38454500988).

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

21033123012 is a wasteful number, since it uses less digits than its factorization.

21033123012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17704673 (or 17704665 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

Adding to 21033123012 its reverse (21032133012), we get a palindrome (42065256024).

The spelling of 21033123012 in words is "twenty-one billion, thirty-three million, one hundred twenty-three thousand, twelve".