21152212542 has 24 divisors (see below), whose sum is σ = 46137382200. Its totient is φ = 7003416240.

The previous prime is 21152212541. The next prime is 21152212573. The reversal of 21152212542 is 24521225112.

21152212542 is a `hidden beast` number, since 2 + 11 + 522 + 125 + 4 + 2 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21152212541) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3940684 + ... + 3946047.

It is an arithmetic number, because the mean of its divisors is an integer number (1922390925).

Almost surely, 2^21152212542 is an apocalyptic number.

21152212542 is an abundant number, since it is smaller than the sum of its proper divisors (24985169658).

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

21152212542 is a wasteful number, since it uses less digits than its factorization.

21152212542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7886888 (or 7886885 counting only the distinct ones).

The product of its digits is 3200, while the sum is 27.

Adding to 21152212542 its reverse (24521225112), we get a palindrome (45673437654).

The spelling of 21152212542 in words is "twenty-one billion, one hundred fifty-two million, two hundred twelve thousand, five hundred forty-two".