21231312000 has 128 divisors (see below), whose sum is σ = 70381958400. Its totient is φ = 5661670400.

The previous prime is 21231311989. The next prime is 21231312007. The reversal of 21231312000 is 21313212.

It is a tau number, because it is divible by the number of its divisors (128).

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

It is not an unprimeable number, because it can be changed into a prime (21231312007) 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, 173160 + ... + 269159.

It is an arithmetic number, because the mean of its divisors is an integer number (549859050).

Almost surely, 2^21231312000 is an apocalyptic number.

21231312000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21231312000 is an abundant number, since it is smaller than the sum of its proper divisors (49150646400).

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

21231312000 is an equidigital number, since it uses as much as digits as its factorization.

21231312000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 442351 (or 442329 counting only the distinct ones).

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

Adding to 21231312000 its reverse (21313212), we get a palindrome (21252625212).

The spelling of 21231312000 in words is "twenty-one billion, two hundred thirty-one million, three hundred twelve thousand".