21298915 has 8 divisors (see below), whose sum is σ = 27882288. Its totient is φ = 15490080.

The previous prime is 21298903. The next prime is 21298931. The reversal of 21298915 is 51989212.

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

It is not a de Polignac number, because 21298915 - 2⁵ = 21298883 is a prime.

It is a Duffinian number.

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, 193572 + ... + 193681.

It is an arithmetic number, because the mean of its divisors is an integer number (3485286).

Almost surely, 2^21298915 is an apocalyptic number.

21298915 is a deficient number, since it is larger than the sum of its proper divisors (6583373).

21298915 is a wasteful number, since it uses less digits than its factorization.

21298915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 387269.

The product of its digits is 12960, while the sum is 37.

The square root of 21298915 is about 4615.0747556242. The cubic root of 21298915 is about 277.1952773347.

The spelling of 21298915 in words is "twenty-one million, two hundred ninety-eight thousand, nine hundred fifteen".