21005695 has 8 divisors (see below), whose sum is σ = 25231536. Its totient is φ = 16788096.

The previous prime is 21005689. The next prime is 21005701. The reversal of 21005695 is 59650012.

It is an interprime number because it is at equal distance from previous prime (21005689) and next prime (21005701).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21005695 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8244 + ... + 10486.

It is an arithmetic number, because the mean of its divisors is an integer number (3153942).

Almost surely, 2^21005695 is an apocalyptic number.

21005695 is a deficient number, since it is larger than the sum of its proper divisors (4225841).

21005695 is a wasteful number, since it uses less digits than its factorization.

21005695 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4121.

The product of its (nonzero) digits is 2700, while the sum is 28.

The square root of 21005695 is about 4583.1970282762. The cubic root of 21005695 is about 275.9173551827.

The spelling of 21005695 in words is "twenty-one million, five thousand, six hundred ninety-five".