21042115 has 8 divisors (see below), whose sum is σ = 25275600. Its totient is φ = 16816992.

The previous prime is 21042103. The next prime is 21042127. The reversal of 21042115 is 51124012.

It is an interprime number because it is at equal distance from previous prime (21042103) and next prime (21042127).

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 21042115 - 2¹⁷ = 20911043 is a prime.

It is a super-3 number, since 3×21042115³ (a number of 23 digits) contains 333 as substring.

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, 7257 + ... + 9733.

It is an arithmetic number, because the mean of its divisors is an integer number (3159450).

Almost surely, 2^21042115 is an apocalyptic number.

21042115 is a deficient number, since it is larger than the sum of its proper divisors (4233485).

21042115 is a wasteful number, since it uses less digits than its factorization.

21042115 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4181.

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 21042115 is about 4587.1685166342. The cubic root of 21042115 is about 276.0767263756.

Adding to 21042115 its reverse (51124012), we get a palindrome (72166127).

The spelling of 21042115 in words is "twenty-one million, forty-two thousand, one hundred fifteen".