21510220314021 has 4 divisors (see below), whose sum is σ = 28680293752032. Its totient is φ = 14340146876012.

The previous prime is 21510220314019. The next prime is 21510220314029. The reversal of 21510220314021 is 12041302201512.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21510220314021 - 2¹ = 21510220314019 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21510220313982 and 21510220314000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21510220314029) 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, 3585036719001 + ... + 3585036719006.

It is an arithmetic number, because the mean of its divisors is an integer number (7170073438008).

Almost surely, 2^{21510220314021} is an apocalyptic number.

It is an amenable number.

21510220314021 is a deficient number, since it is larger than the sum of its proper divisors (7170073438011).

21510220314021 is an equidigital number, since it uses as much as digits as its factorization.

21510220314021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7170073438010.

The product of its (nonzero) digits is 960, while the sum is 24.

Adding to 21510220314021 its reverse (12041302201512), we get a palindrome (33551522515533).

The spelling of 21510220314021 in words is "twenty-one trillion, five hundred ten billion, two hundred twenty million, three hundred fourteen thousand, twenty-one".