21495915 has 96 divisors (see below), whose sum is σ = 46717440. Its totient is φ = 9180864.

The previous prime is 21495913. The next prime is 21495917. The reversal of 21495915 is 51959412.

21495915 is a `hidden beast` number, since 21 + 49 + 591 + 5 = 666.

It is an interprime number because it is at equal distance from previous prime (21495913) and next prime (21495917).

It is not a de Polignac number, because 21495915 - 2¹ = 21495913 is a prime.

Its product of digits (16200) is a multiple of the sum of its prime divisors (81).

It is a self number, because there is not a number n which added to its sum of digits gives 21495915.

It is not an unprimeable number, because it can be changed into a prime (21495911) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 499884 + ... + 499926.

It is an arithmetic number, because the mean of its divisors is an integer number (486640).

Almost surely, 2^21495915 is an apocalyptic number.

21495915 is an abundant number, since it is smaller than the sum of its proper divisors (25221525).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21495915 is a wasteful number, since it uses less digits than its factorization.

21495915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110 (or 81 counting only the distinct ones).

The product of its digits is 16200, while the sum is 36.

The square root of 21495915 is about 4636.3687299437. The cubic root of 21495915 is about 278.0472764343.

The spelling of 21495915 in words is "twenty-one million, four hundred ninety-five thousand, nine hundred fifteen".