21321013 has 8 divisors (see below), whose sum is σ = 24394880. Its totient is φ = 18254160.

The previous prime is 21320987. The next prime is 21321019. The reversal of 21321013 is 31012312.

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 21321013 - 2²¹ = 19223861 is a prime.

It is a Duffinian number.

It is a plaindrome in base 13.

It is a junction number, because it is equal to n+sod(n) for n = 21320984 and 21321002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21321019) 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, 10408 + ... + 12286.

It is an arithmetic number, because the mean of its divisors is an integer number (3049360).

Almost surely, 2^21321013 is an apocalyptic number.

It is an amenable number.

21321013 is a deficient number, since it is larger than the sum of its proper divisors (3073867).

21321013 is a wasteful number, since it uses less digits than its factorization.

21321013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3507.

The product of its (nonzero) digits is 36, while the sum is 13.

The square root of 21321013 is about 4617.4682456948. The cubic root of 21321013 is about 277.2911091964.

Adding to 21321013 its reverse (31012312), we get a palindrome (52333325).

The spelling of 21321013 in words is "twenty-one million, three hundred twenty-one thousand, thirteen".