21295705 has 4 divisors (see below), whose sum is σ = 25554852. Its totient is φ = 17036560.

The previous prime is 21295697. The next prime is 21295709. The reversal of 21295705 is 50759212.

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

It can be written as a sum of positive squares in 2 ways, for example, as 12845056 + 8450649 = 3584^2 + 2907^2 .

It is not a de Polignac number, because 21295705 - 2³ = 21295697 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21295709) 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, 2129566 + ... + 2129575.

It is an arithmetic number, because the mean of its divisors is an integer number (6388713).

Almost surely, 2^21295705 is an apocalyptic number.

It is an amenable number.

21295705 is a deficient number, since it is larger than the sum of its proper divisors (4259147).

21295705 is an equidigital number, since it uses as much as digits as its factorization.

21295705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4259146.

The product of its (nonzero) digits is 6300, while the sum is 31.

The square root of 21295705 is about 4614.7269691716. The cubic root of 21295705 is about 277.1813510925.

The spelling of 21295705 in words is "twenty-one million, two hundred ninety-five thousand, seven hundred five".