20689605 has 24 divisors (see below), whose sum is σ = 36048480. Its totient is φ = 10977120.

The previous prime is 20689583. The next prime is 20689619. The reversal of 20689605 is 50698602.

It is not a de Polignac number, because 20689605 - 2⁷ = 20689477 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20689605.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8406 + ... + 10584.

It is an arithmetic number, because the mean of its divisors is an integer number (1502020).

Almost surely, 2^20689605 is an apocalyptic number.

It is an amenable number.

20689605 is a deficient number, since it is larger than the sum of its proper divisors (15358875).

20689605 is a wasteful number, since it uses less digits than its factorization.

20689605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2401 (or 2398 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The square root of 20689605 is about 4548.5827463068. The cubic root of 20689605 is about 274.5263693103.

The spelling of 20689605 in words is "twenty million, six hundred eighty-nine thousand, six hundred five".