21523312542 has 8 divisors (see below), whose sum is σ = 43046625096. Its totient is φ = 7174437512.

The previous prime is 21523312523. The next prime is 21523312543. The reversal of 21523312542 is 24521332512.

It is a sphenic number, since it is the product of 3 distinct primes.

21523312542 is an admirable number.

It is a super-2 number, since 2×21523312542² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21523312543) 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 3 ways as a sum of consecutive naturals, for example, 1793609373 + ... + 1793609384.

It is an arithmetic number, because the mean of its divisors is an integer number (5380828137).

Almost surely, 2^21523312542 is an apocalyptic number.

21523312542 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21523312542 is a wasteful number, since it uses less digits than its factorization.

21523312542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3587218762.

The product of its digits is 14400, while the sum is 30.

The spelling of 21523312542 in words is "twenty-one billion, five hundred twenty-three million, three hundred twelve thousand, five hundred forty-two".