20624647 has 4 divisors (see below), whose sum is σ = 20807280. Its totient is φ = 20442016.

The previous prime is 20624623. The next prime is 20624657. The reversal of 20624647 is 74642602.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20624647 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20624657) 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 3 ways as a sum of consecutive naturals, for example, 91147 + ... + 91372.

It is an arithmetic number, because the mean of its divisors is an integer number (5201820).

Almost surely, 2^20624647 is an apocalyptic number.

20624647 is the 2428-th centered heptagonal number.

20624647 is a deficient number, since it is larger than the sum of its proper divisors (182633).

20624647 is a wasteful number, since it uses less digits than its factorization.

20624647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 182632.

The product of its (nonzero) digits is 16128, while the sum is 31.

The square root of 20624647 is about 4541.4366669590. The cubic root of 20624647 is about 274.2387630578.

The spelling of 20624647 in words is "twenty million, six hundred twenty-four thousand, six hundred forty-seven".