21302121 has 8 divisors (see below), whose sum is σ = 29170624. Its totient is φ = 13817520.

The previous prime is 21302111. The next prime is 21302123. The reversal of 21302121 is 12120312.

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

It is not a de Polignac number, because 21302121 - 2¹⁰ = 21301097 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21302097 and 21302106.

It is not an unprimeable number, because it can be changed into a prime (21302123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 95845 + ... + 96066.

It is an arithmetic number, because the mean of its divisors is an integer number (3646328).

Almost surely, 2^21302121 is an apocalyptic number.

It is an amenable number.

21302121 is a deficient number, since it is larger than the sum of its proper divisors (7868503).

21302121 is a wasteful number, since it uses less digits than its factorization.

21302121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191951.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 21302121 is about 4615.4220825402. The cubic root of 21302121 is about 277.2091848267.

Adding to 21302121 its reverse (12120312), we get a palindrome (33422433).

The spelling of 21302121 in words is "twenty-one million, three hundred two thousand, one hundred twenty-one".