21131242732 has 12 divisors (see below), whose sum is σ = 38587486896. Its totient is φ = 10106246480.

The previous prime is 21131242703. The next prime is 21131242733. The reversal of 21131242732 is 23724213112.

It is a self number, because there is not a number n which added to its sum of digits gives 21131242732.

It is not an unprimeable number, because it can be changed into a prime (21131242733) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 114843619 + ... + 114843802.

It is an arithmetic number, because the mean of its divisors is an integer number (3215623908).

Almost surely, 2^21131242732 is an apocalyptic number.

It is an amenable number.

21131242732 is a deficient number, since it is larger than the sum of its proper divisors (17456244164).

21131242732 is a wasteful number, since it uses less digits than its factorization.

21131242732 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 229687448 (or 229687446 counting only the distinct ones).

The product of its digits is 4032, while the sum is 28.

Adding to 21131242732 its reverse (23724213112), we get a palindrome (44855455844).

The spelling of 21131242732 in words is "twenty-one billion, one hundred thirty-one million, two hundred forty-two thousand, seven hundred thirty-two".