21695087 has 2 divisors, whose sum is σ = 21695088. Its totient is φ = 21695086.

The previous prime is 21695083. The next prime is 21695099. The reversal of 21695087 is 78059612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21695087 - 2² = 21695083 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21695087.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21695081) 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 as a sum of consecutive naturals, namely, 10847543 + 10847544.

It is an arithmetic number, because the mean of its divisors is an integer number (10847544).

Almost surely, 2^21695087 is an apocalyptic number.

21695087 is a deficient number, since it is larger than the sum of its proper divisors (1).

21695087 is an equidigital number, since it uses as much as digits as its factorization.

21695087 is an odious number, because the sum of its binary digits is odd.

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

The square root of 21695087 is about 4657.7985143198. The cubic root of 21695087 is about 278.9033936244.

The spelling of 21695087 in words is "twenty-one million, six hundred ninety-five thousand, eighty-seven".