21875715 has 24 divisors (see below), whose sum is σ = 39227760. Its totient is φ = 11264064.

The previous prime is 21875713. The next prime is 21875747. The reversal of 21875715 is 51757812.

21875715 is a `hidden beast` number, since 2 + 1 + 87 + 571 + 5 = 666.

It is not a de Polignac number, because 21875715 - 2¹ = 21875713 is a prime.

It is a super-2 number, since 2×21875715² = 957093813522450, 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 21875715.

It is not an unprimeable number, because it can be changed into a prime (21875713) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 7077 + ... + 9686.

It is an arithmetic number, because the mean of its divisors is an integer number (1634490).

Almost surely, 2^21875715 is an apocalyptic number.

21875715 is a deficient number, since it is larger than the sum of its proper divisors (17352045).

21875715 is a wasteful number, since it uses less digits than its factorization.

21875715 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16803 (or 16800 counting only the distinct ones).

The product of its digits is 19600, while the sum is 36.

The square root of 21875715 is about 4677.1481695580. The cubic root of 21875715 is about 279.6752825827.

The spelling of 21875715 in words is "twenty-one million, eight hundred seventy-five thousand, seven hundred fifteen".