20517965 has 16 divisors (see below), whose sum is σ = 26611200. Its totient is φ = 15097152.

The previous prime is 20517961. The next prime is 20517983. The reversal of 20517965 is 56971502.

It is a cyclic number.

It is not a de Polignac number, because 20517965 - 2² = 20517961 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20517961) 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 15 ways as a sum of consecutive naturals, for example, 30806 + ... + 31464.

It is an arithmetic number, because the mean of its divisors is an integer number (1663200).

Almost surely, 2^20517965 is an apocalyptic number.

It is an amenable number.

20517965 is a deficient number, since it is larger than the sum of its proper divisors (6093235).

20517965 is a wasteful number, since it uses less digits than its factorization.

20517965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1156.

The product of its (nonzero) digits is 18900, while the sum is 35.

The square root of 20517965 is about 4529.6760369810. The cubic root of 20517965 is about 273.7651076224.

The spelling of 20517965 in words is "twenty million, five hundred seventeen thousand, nine hundred sixty-five".