20687657 has 16 divisors (see below), whose sum is σ = 22825152. Its totient is φ = 18670080.

The previous prime is 20687627. The next prime is 20687659. The reversal of 20687657 is 75678602.

It is a happy number.

It is not a de Polignac number, because 20687657 - 2⁶ = 20687593 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (41).

It is not an unprimeable number, because it can be changed into a prime (20687659) 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, 46478 + ... + 46920.

It is an arithmetic number, because the mean of its divisors is an integer number (1426572).

Almost surely, 2^20687657 is an apocalyptic number.

It is an amenable number.

20687657 is a deficient number, since it is larger than the sum of its proper divisors (2137495).

20687657 is a wasteful number, since it uses less digits than its factorization.

20687657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 568.

The product of its (nonzero) digits is 141120, while the sum is 41.

The square root of 20687657 is about 4548.3686086332. The cubic root of 20687657 is about 274.5177531614.

The spelling of 20687657 in words is "twenty million, six hundred eighty-seven thousand, six hundred fifty-seven".