21087695 has 4 divisors (see below), whose sum is σ = 25305240. Its totient is φ = 16870152.

The previous prime is 21087691. The next prime is 21087713. The reversal of 21087695 is 59678012.

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 21087695 - 2² = 21087691 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21087691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2108765 + ... + 2108774.

It is an arithmetic number, because the mean of its divisors is an integer number (6326310).

Almost surely, 2^21087695 is an apocalyptic number.

21087695 is a deficient number, since it is larger than the sum of its proper divisors (4217545).

21087695 is an equidigital number, since it uses as much as digits as its factorization.

21087695 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4217544.

The product of its (nonzero) digits is 30240, while the sum is 38.

The square root of 21087695 is about 4592.1340355003. The cubic root of 21087695 is about 276.2759221664.

The spelling of 21087695 in words is "twenty-one million, eighty-seven thousand, six hundred ninety-five".