20687538 has 32 divisors (see below), whose sum is σ = 44181504. Its totient is φ = 6435072.

The previous prime is 20687533. The next prime is 20687539. The reversal of 20687538 is 83578602.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20687496 and 20687505.

It is not an unprimeable number, because it can be changed into a prime (20687533) 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, 12156 + ... + 13752.

It is an arithmetic number, because the mean of its divisors is an integer number (1380672).

Almost surely, 2^20687538 is an apocalyptic number.

20687538 is an abundant number, since it is smaller than the sum of its proper divisors (23493966).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20687538 is a wasteful number, since it uses less digits than its factorization.

20687538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1746.

The product of its (nonzero) digits is 80640, while the sum is 39.

The square root of 20687538 is about 4548.3555270009. The cubic root of 20687538 is about 274.5172267980.

The spelling of 20687538 in words is "twenty million, six hundred eighty-seven thousand, five hundred thirty-eight".