21700117 has 2 divisors, whose sum is σ = 21700118. Its totient is φ = 21700116.

The previous prime is 21700103. The next prime is 21700123. The reversal of 21700117 is 71100712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21659716 + 40401 = 4654^2 + 201^2 .

It is a cyclic number.

It is not a de Polignac number, because 21700117 - 2²³ = 13311509 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21700094 and 21700103.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21700127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10850058 + 10850059.

It is an arithmetic number, because the mean of its divisors is an integer number (10850059).

Almost surely, 2^21700117 is an apocalyptic number.

It is an amenable number.

21700117 is a deficient number, since it is larger than the sum of its proper divisors (1).

21700117 is an equidigital number, since it uses as much as digits as its factorization.

21700117 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 98, while the sum is 19.

The square root of 21700117 is about 4658.3384376835. The cubic root of 21700117 is about 278.9249465174.

Adding to 21700117 its reverse (71100712), we get a palindrome (92800829).

The spelling of 21700117 in words is "twenty-one million, seven hundred thousand, one hundred seventeen".