21100317 has 16 divisors (see below), whose sum is σ = 33845760. Its totient is φ = 11422512.

The previous prime is 21100297. The next prime is 21100319. The reversal of 21100317 is 71300112.

It is not a de Polignac number, because 21100317 - 2⁶ = 21100253 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21100296 and 21100305.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100319) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26043 + ... + 26840.

It is an arithmetic number, because the mean of its divisors is an integer number (2115360).

Almost surely, 2^21100317 is an apocalyptic number.

It is an amenable number.

21100317 is a deficient number, since it is larger than the sum of its proper divisors (12745443).

21100317 is a wasteful number, since it uses less digits than its factorization.

21100317 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52912.

The product of its (nonzero) digits is 42, while the sum is 15.

The square root of 21100317 is about 4593.5081364900. The cubic root of 21100317 is about 276.3310326495.

Adding to 21100317 its reverse (71300112), we get a palindrome (92400429).

The spelling of 21100317 in words is "twenty-one million, one hundred thousand, three hundred seventeen".