20689697 has 24 divisors (see below), whose sum is σ = 25933824. Its totient is φ = 16111872.

The previous prime is 20689661. The next prime is 20689699. The reversal of 20689697 is 79698602.

It is not a de Polignac number, because 20689697 - 2⁶ = 20689633 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20689699) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 162848 + ... + 162974.

It is an arithmetic number, because the mean of its divisors is an integer number (1080576).

Almost surely, 2^20689697 is an apocalyptic number.

It is an amenable number.

20689697 is a deficient number, since it is larger than the sum of its proper divisors (5244127).

20689697 is a wasteful number, since it uses less digits than its factorization.

20689697 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 225 (or 188 counting only the distinct ones).

The product of its (nonzero) digits is 326592, while the sum is 47.

The square root of 20689697 is about 4548.5928593357. The cubic root of 20689697 is about 274.5267762198.

The spelling of 20689697 in words is "twenty million, six hundred eighty-nine thousand, six hundred ninety-seven".