20641487 has 4 divisors (see below), whose sum is σ = 20723976. Its totient is φ = 20559000.

The previous prime is 20641483. The next prime is 20641493. The reversal of 20641487 is 78414602.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20641487 - 2² = 20641483 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 (20641483) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40868 + ... + 41369.

It is an arithmetic number, because the mean of its divisors is an integer number (5180994).

Almost surely, 2^20641487 is an apocalyptic number.

20641487 is a deficient number, since it is larger than the sum of its proper divisors (82489).

20641487 is an equidigital number, since it uses as much as digits as its factorization.

20641487 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82488.

The product of its (nonzero) digits is 10752, while the sum is 32.

The square root of 20641487 is about 4543.2903275049. The cubic root of 20641487 is about 274.3133812953.

The spelling of 20641487 in words is "twenty million, six hundred forty-one thousand, four hundred eighty-seven".