21121115 has 8 divisors (see below), whose sum is σ = 25775280. Its totient is φ = 16610272.

The previous prime is 21121099. The next prime is 21121129. The reversal of 21121115 is 51112112.

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 21121115 - 2⁴ = 21121099 is a prime.

It is a super-2 number, since 2×21121115² = 892202997686450, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21121115.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35504 + ... + 36093.

It is an arithmetic number, because the mean of its divisors is an integer number (3221910).

Almost surely, 2^21121115 is an apocalyptic number.

21121115 is a deficient number, since it is larger than the sum of its proper divisors (4654165).

21121115 is an equidigital number, since it uses as much as digits as its factorization.

21121115 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71661.

The product of its digits is 20, while the sum is 14.

The square root of 21121115 is about 4595.7714259959. The cubic root of 21121115 is about 276.4217934595.

Adding to 21121115 its reverse (51112112), we get a palindrome (72233227).

The spelling of 21121115 in words is "twenty-one million, one hundred twenty-one thousand, one hundred fifteen".