20551687 has 8 divisors (see below), whose sum is σ = 22731296. Its totient is φ = 18457632.

The previous prime is 20551637. The next prime is 20551697. The reversal of 20551687 is 78615502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20551687 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20551607) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20883 + ... + 21844.

It is an arithmetic number, because the mean of its divisors is an integer number (2841412).

Almost surely, 2^20551687 is an apocalyptic number.

20551687 is a deficient number, since it is larger than the sum of its proper divisors (2179609).

20551687 is a wasteful number, since it uses less digits than its factorization.

20551687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42777.

The product of its (nonzero) digits is 16800, while the sum is 34.

The square root of 20551687 is about 4533.3968500452. The cubic root of 20551687 is about 273.9150064049.

The spelling of 20551687 in words is "twenty million, five hundred fifty-one thousand, six hundred eighty-seven".