21023121005 has 8 divisors (see below), whose sum is σ = 25229318400. Its totient is φ = 16817448016.

The previous prime is 21023121001. The next prime is 21023121037. The reversal of 21023121005 is 50012132012.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21023121005 - 2² = 21023121001 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21023121001) 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 in 7 ways as a sum of consecutive naturals, for example, 36725 + ... + 208314.

It is an arithmetic number, because the mean of its divisors is an integer number (3153664800).

Almost surely, 2^21023121005 is an apocalyptic number.

It is an amenable number.

21023121005 is a deficient number, since it is larger than the sum of its proper divisors (4206197395).

21023121005 is a wasteful number, since it uses less digits than its factorization.

21023121005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 262203.

The product of its (nonzero) digits is 120, while the sum is 17.

Adding to 21023121005 its reverse (50012132012), we get a palindrome (71035253017).

The spelling of 21023121005 in words is "twenty-one billion, twenty-three million, one hundred twenty-one thousand, five".