21700917 has 24 divisors (see below), whose sum is σ = 35954880. Its totient is φ = 12355200.

The previous prime is 21700901. The next prime is 21700949. The reversal of 21700917 is 71900712.

It is not a de Polignac number, because 21700917 - 2⁴ = 21700901 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21700957) 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 23 ways as a sum of consecutive naturals, for example, 24834 + ... + 25692.

It is an arithmetic number, because the mean of its divisors is an integer number (1498120).

Almost surely, 2^21700917 is an apocalyptic number.

It is an amenable number.

21700917 is a deficient number, since it is larger than the sum of its proper divisors (14253963).

21700917 is a wasteful number, since it uses less digits than its factorization.

21700917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1273 (or 1270 counting only the distinct ones).

The product of its (nonzero) digits is 882, while the sum is 27.

The square root of 21700917 is about 4658.4243044188. The cubic root of 21700917 is about 278.9283741059.

The spelling of 21700917 in words is "twenty-one million, seven hundred thousand, nine hundred seventeen".