21395017 has 12 divisors (see below), whose sum is σ = 25207680. Its totient is φ = 18103176.

The previous prime is 21394949. The next prime is 21395021. The reversal of 21395017 is 71059312.

It is not a de Polignac number, because 21395017 - 2⁷ = 21394889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21395047) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1108 + ... + 6634.

It is an arithmetic number, because the mean of its divisors is an integer number (2100640).

Almost surely, 2^21395017 is an apocalyptic number.

It is an amenable number.

21395017 is a deficient number, since it is larger than the sum of its proper divisors (3812663).

21395017 is an equidigital number, since it uses as much as digits as its factorization.

21395017 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5620 (or 5613 counting only the distinct ones).

The product of its (nonzero) digits is 1890, while the sum is 28.

The square root of 21395017 is about 4625.4747864408. The cubic root of 21395017 is about 277.6115591820.

The spelling of 21395017 in words is "twenty-one million, three hundred ninety-five thousand, seventeen".