21012320142 has 48 divisors (see below), whose sum is σ = 49765248000. Its totient is φ = 6354579600.

The previous prime is 21012320117. The next prime is 21012320143. The reversal of 21012320142 is 24102321012.

It is a happy number.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012320143) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7534 + ... + 205137.

It is an arithmetic number, because the mean of its divisors is an integer number (1036776000).

Almost surely, 2^21012320142 is an apocalyptic number.

21012320142 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21012320142 is an abundant number, since it is smaller than the sum of its proper divisors (28752927858).

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

21012320142 is a wasteful number, since it uses less digits than its factorization.

21012320142 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213189 (or 213186 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 21012320142 its reverse (24102321012), we get a palindrome (45114641154).

The spelling of 21012320142 in words is "twenty-one billion, twelve million, three hundred twenty thousand, one hundred forty-two".