20520643 has 8 divisors (see below), whose sum is σ = 24108336. Its totient is φ = 17220000.

The previous prime is 20520629. The next prime is 20520653. The reversal of 20520643 is 34602502.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 20520643 - 2²¹ = 18423491 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20520653) 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 7 ways as a sum of consecutive naturals, for example, 71608 + ... + 71893.

It is an arithmetic number, because the mean of its divisors is an integer number (3013542).

Almost surely, 2^20520643 is an apocalyptic number.

20520643 is a deficient number, since it is larger than the sum of its proper divisors (3587693).

20520643 is a wasteful number, since it uses less digits than its factorization.

20520643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143525.

The product of its (nonzero) digits is 1440, while the sum is 22.

The square root of 20520643 is about 4529.9716334653. The cubic root of 20520643 is about 273.7770176902. Note that the first 3 decimals are identical.

The spelling of 20520643 in words is "twenty million, five hundred twenty thousand, six hundred forty-three".