20687500 has 42 divisors (see below), whose sum is σ = 45390044. Its totient is φ = 8250000.

The previous prime is 20687497. The next prime is 20687503. The reversal of 20687500 is 578602.

It is an interprime number because it is at equal distance from previous prime (20687497) and next prime (20687503).

It is not an unprimeable number, because it can be changed into a prime (20687503) 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 13 ways as a sum of consecutive naturals, for example, 62335 + ... + 62665.

Almost surely, 2^20687500 is an apocalyptic number.

20687500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20687500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22695022).

20687500 is an abundant number, since it is smaller than the sum of its proper divisors (24702544).

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

20687500 is an frugal number, since it uses more digits than its factorization.

20687500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 365 (or 338 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 20687500 is about 4548.3513496651. The cubic root of 20687500 is about 274.5170587152.

The spelling of 20687500 in words is "twenty million, six hundred eighty-seven thousand, five hundred".