20956123 has 4 divisors (see below), whose sum is σ = 21299728. Its totient is φ = 20612520.

The previous prime is 20956109. The next prime is 20956129. The reversal of 20956123 is 32165902.

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 20956123 - 2²¹ = 18858971 is a prime.

It is a super-2 number, since 2×20956123² = 878318182382258, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20956091 and 20956100.

It is not an unprimeable number, because it can be changed into a prime (20956129) 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, 171711 + ... + 171832.

It is an arithmetic number, because the mean of its divisors is an integer number (5324932).

Almost surely, 2^20956123 is an apocalyptic number.

20956123 is a deficient number, since it is larger than the sum of its proper divisors (343605).

20956123 is an equidigital number, since it uses as much as digits as its factorization.

20956123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 343604.

The product of its (nonzero) digits is 3240, while the sum is 28.

The square root of 20956123 is about 4577.7858184935. The cubic root of 20956123 is about 275.7001355382.

The spelling of 20956123 in words is "twenty million, nine hundred fifty-six thousand, one hundred twenty-three".