21095647 has 4 divisors (see below), whose sum is σ = 21114016. Its totient is φ = 21077280.

The previous prime is 21095629. The next prime is 21095653. The reversal of 21095647 is 74659012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21095647 - 2¹⁹ = 20571359 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21095617) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7338 + ... + 9799.

It is an arithmetic number, because the mean of its divisors is an integer number (5278504).

Almost surely, 2^21095647 is an apocalyptic number.

21095647 is a deficient number, since it is larger than the sum of its proper divisors (18369).

21095647 is a wasteful number, since it uses less digits than its factorization.

21095647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18368.

The product of its (nonzero) digits is 15120, while the sum is 34.

The square root of 21095647 is about 4592.9997822774. Note that the first 3 decimals coincide. The cubic root of 21095647 is about 276.3106449441.

The spelling of 21095647 in words is "twenty-one million, ninety-five thousand, six hundred forty-seven".