21030217321 has 4 divisors (see below), whose sum is σ = 21374975044. Its totient is φ = 20685459600.

The previous prime is 21030217277. The next prime is 21030217331. The reversal of 21030217321 is 12371203012.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 7652750400 + 13377466921 = 87480^2 + 115661^2 .

It is a cyclic number.

It is not a de Polignac number, because 21030217321 - 2¹³ = 21030209129 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21030217292 and 21030217301.

It is not an unprimeable number, because it can be changed into a prime (21030217331) 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, 172378770 + ... + 172378891.

It is an arithmetic number, because the mean of its divisors is an integer number (5343743761).

Almost surely, 2^21030217321 is an apocalyptic number.

It is an amenable number.

21030217321 is a deficient number, since it is larger than the sum of its proper divisors (344757723).

21030217321 is an equidigital number, since it uses as much as digits as its factorization.

21030217321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 344757722.

The product of its (nonzero) digits is 504, while the sum is 22.

The spelling of 21030217321 in words is "twenty-one billion, thirty million, two hundred seventeen thousand, three hundred twenty-one".