21207115 has 8 divisors (see below), whose sum is σ = 25605648. Its totient is φ = 16860960.

The previous prime is 21207107. The next prime is 21207133. The reversal of 21207115 is 51170212.

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

It is not a de Polignac number, because 21207115 - 2³ = 21207107 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21207092 and 21207101.

It is an unprimeable number.

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, 12196 + ... + 13825.

It is an arithmetic number, because the mean of its divisors is an integer number (3200706).

Almost surely, 2^21207115 is an apocalyptic number.

21207115 is a deficient number, since it is larger than the sum of its proper divisors (4398533).

21207115 is a wasteful number, since it uses less digits than its factorization.

21207115 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26189.

The product of its (nonzero) digits is 140, while the sum is 19.

The square root of 21207115 is about 4605.1183480992. The cubic root of 21207115 is about 276.7964593183.

Adding to 21207115 its reverse (51170212), we get a palindrome (72377327).

The spelling of 21207115 in words is "twenty-one million, two hundred seven thousand, one hundred fifteen".