20956543 has 4 divisors (see below), whose sum is σ = 21004720. Its totient is φ = 20908368.

The previous prime is 20956511. The next prime is 20956583. The reversal of 20956543 is 34565902.

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 20956543 - 2⁵ = 20956511 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20956499 and 20956508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20956583) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23430 + ... + 24307.

It is an arithmetic number, because the mean of its divisors is an integer number (5251180).

Almost surely, 2^20956543 is an apocalyptic number.

20956543 is a deficient number, since it is larger than the sum of its proper divisors (48177).

20956543 is an equidigital number, since it uses as much as digits as its factorization.

20956543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48176.

The product of its (nonzero) digits is 32400, while the sum is 34.

The square root of 20956543 is about 4577.8316919695. The cubic root of 20956543 is about 275.7019773752.

The spelling of 20956543 in words is "twenty million, nine hundred fifty-six thousand, five hundred forty-three".