20355657 has 16 divisors (see below), whose sum is σ = 31605120. Its totient is φ = 11411712.

The previous prime is 20355637. The next prime is 20355689. The reversal of 20355657 is 75655302.

It is not a de Polignac number, because 20355657 - 2¹¹ = 20353609 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20355607) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8032 + ... + 10257.

It is an arithmetic number, because the mean of its divisors is an integer number (1975320).

Almost surely, 2^20355657 is an apocalyptic number.

It is an amenable number.

20355657 is a deficient number, since it is larger than the sum of its proper divisors (11249463).

20355657 is a wasteful number, since it uses less digits than its factorization.

20355657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18352.

The product of its (nonzero) digits is 31500, while the sum is 33.

The square root of 20355657 is about 4511.7243931783. The cubic root of 20355657 is about 273.0413199409.

It can be divided in two parts, 20355 and 657, that added together give a palindrome (21012).

The spelling of 20355657 in words is "twenty million, three hundred fifty-five thousand, six hundred fifty-seven".