21131310021 has 8 divisors (see below), whose sum is σ = 28322594304. Its totient is φ = 14013782880.

The previous prime is 21131309993. The next prime is 21131310037. The reversal of 21131310021 is 12001313112.

It is a happy number.

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

It is not a de Polignac number, because 21131310021 - 2¹¹ = 21131307973 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21131310041) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18438616 + ... + 18439761.

It is an arithmetic number, because the mean of its divisors is an integer number (3540324288).

Almost surely, 2^21131310021 is an apocalyptic number.

It is an amenable number.

21131310021 is a deficient number, since it is larger than the sum of its proper divisors (7191284283).

21131310021 is a wasteful number, since it uses less digits than its factorization.

21131310021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36878571.

The product of its (nonzero) digits is 36, while the sum is 15.

Adding to 21131310021 its reverse (12001313112), we get a palindrome (33132623133).

The spelling of 21131310021 in words is "twenty-one billion, one hundred thirty-one million, three hundred ten thousand, twenty-one".