21131123102 has 4 divisors (see below), whose sum is σ = 31696684656. Its totient is φ = 10565561550.

The previous prime is 21131123077. The next prime is 21131123107. The reversal of 21131123102 is 20132113112.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21131123107) 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 as a sum of consecutive naturals, namely, 5282780774 + ... + 5282780777.

It is an arithmetic number, because the mean of its divisors is an integer number (7924171164).

Almost surely, 2^21131123102 is an apocalyptic number.

21131123102 is a deficient number, since it is larger than the sum of its proper divisors (10565561554).

21131123102 is a wasteful number, since it uses less digits than its factorization.

21131123102 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10565561553.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 21131123102 its reverse (20132113112), we get a palindrome (41263236214).

The spelling of 21131123102 in words is "twenty-one billion, one hundred thirty-one million, one hundred twenty-three thousand, one hundred two".