21531112542 has 24 divisors (see below), whose sum is σ = 46653496344. Its totient is φ = 7176614064.

The previous prime is 21531112517. The next prime is 21531112573. The reversal of 21531112542 is 24521113512.

It is a happy number.

21531112542 is a `hidden beast` number, since 2 + 1 + 5 + 3 + 1 + 112 + 542 = 666.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 487948 + ... + 530240.

It is an arithmetic number, because the mean of its divisors is an integer number (1943895681).

Almost surely, 2^21531112542 is an apocalyptic number.

21531112542 is an abundant number, since it is smaller than the sum of its proper divisors (25122383802).

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

21531112542 is a wasteful number, since it uses less digits than its factorization.

21531112542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70584 (or 70581 counting only the distinct ones).

The product of its digits is 2400, while the sum is 27.

The spelling of 21531112542 in words is "twenty-one billion, five hundred thirty-one million, one hundred twelve thousand, five hundred forty-two".