21415873 has 8 divisors (see below), whose sum is σ = 21888000. Its totient is φ = 20948928.

The previous prime is 21415871. The next prime is 21415931. The reversal of 21415873 is 37851412.

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 21415873 - 2¹ = 21415871 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21415871) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7728 + ... + 10126.

It is an arithmetic number, because the mean of its divisors is an integer number (2736000).

Almost surely, 2^21415873 is an apocalyptic number.

It is an amenable number.

21415873 is a deficient number, since it is larger than the sum of its proper divisors (472127).

21415873 is a wasteful number, since it uses less digits than its factorization.

21415873 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2591.

The product of its digits is 6720, while the sum is 31.

The square root of 21415873 is about 4627.7287085567. The cubic root of 21415873 is about 277.7017357305.

The spelling of 21415873 in words is "twenty-one million, four hundred fifteen thousand, eight hundred seventy-three".