21400017 has 4 divisors (see below), whose sum is σ = 28533360. Its totient is φ = 14266676.

The previous prime is 21400003. The next prime is 21400031. The reversal of 21400017 is 71000412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (21400003) and next prime (21400031).

It is a cyclic number.

It is not a de Polignac number, because 21400017 - 2⁶ = 21399953 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21399969 and 21400005.

It is not an unprimeable number, because it can be changed into a prime (21400037) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3566667 + ... + 3566672.

It is an arithmetic number, because the mean of its divisors is an integer number (7133340).

Almost surely, 2^21400017 is an apocalyptic number.

It is an amenable number.

21400017 is a deficient number, since it is larger than the sum of its proper divisors (7133343).

21400017 is an equidigital number, since it uses as much as digits as its factorization.

21400017 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7133342.

The product of its (nonzero) digits is 56, while the sum is 15.

The square root of 21400017 is about 4626.0152399230. The cubic root of 21400017 is about 277.6331833711.

Adding to 21400017 its reverse (71000412), we get a palindrome (92400429).

The spelling of 21400017 in words is "twenty-one million, four hundred thousand, seventeen".