20645317 has 12 divisors (see below), whose sum is σ = 26199936. Its totient is φ = 16086840.

The previous prime is 20645311. The next prime is 20645321. The reversal of 20645317 is 71354602.

It is not a de Polignac number, because 20645317 - 2¹¹ = 20643269 is a prime.

It is a super-2 number, since 2×20645317² = 852458228060978, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20645311) 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, 18613 + ... + 19690.

It is an arithmetic number, because the mean of its divisors is an integer number (2183328).

Almost surely, 2^20645317 is an apocalyptic number.

It is an amenable number.

20645317 is a deficient number, since it is larger than the sum of its proper divisors (5554619).

20645317 is a wasteful number, since it uses less digits than its factorization.

20645317 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38328 (or 38321 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 28.

The square root of 20645317 is about 4543.7118086428. The cubic root of 20645317 is about 274.3303464051.

Adding to 20645317 its reverse (71354602), we get a palindrome (91999919).

It can be divided in two parts, 2064 and 5317, that added together give a triangular number (7381 = T₁₂₁).

The spelling of 20645317 in words is "twenty million, six hundred forty-five thousand, three hundred seventeen".