21313015 has 12 divisors (see below), whose sum is σ = 25941384. Its totient is φ = 16809936.

The previous prime is 21313001. The next prime is 21313021. The reversal of 21313015 is 51031312.

It is not a de Polignac number, because 21313015 - 2⁷ = 21312887 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21313015.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 30864 + ... + 31546.

It is an arithmetic number, because the mean of its divisors is an integer number (2161782).

Almost surely, 2^21313015 is an apocalyptic number.

21313015 is a deficient number, since it is larger than the sum of its proper divisors (4628369).

21313015 is an frugal number, since it uses more digits than its factorization.

21313015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 846 (or 767 counting only the distinct ones).

The product of its (nonzero) digits is 90, while the sum is 16.

The square root of 21313015 is about 4616.6021054451. The cubic root of 21313015 is about 277.2564321127.

Adding to 21313015 its reverse (51031312), we get a palindrome (72344327).

The spelling of 21313015 in words is "twenty-one million, three hundred thirteen thousand, fifteen".