20956789 has 4 divisors (see below), whose sum is σ = 23950624. Its totient is φ = 17962956.

The previous prime is 20956787. The next prime is 20956799. The reversal of 20956789 is 98765902.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 98765902 = 2 ⋅49382951.

It is a cyclic number.

It is not a de Polignac number, because 20956789 - 2¹ = 20956787 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 (20956787) 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, 1496907 + ... + 1496920.

It is an arithmetic number, because the mean of its divisors is an integer number (5987656).

Almost surely, 2^20956789 is an apocalyptic number.

It is an amenable number.

20956789 is a deficient number, since it is larger than the sum of its proper divisors (2993835).

20956789 is an equidigital number, since it uses as much as digits as its factorization.

20956789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2993834.

The product of its (nonzero) digits is 272160, while the sum is 46.

The square root of 20956789 is about 4577.8585605062. The cubic root of 20956789 is about 275.7030561539.

The spelling of 20956789 in words is "twenty million, nine hundred fifty-six thousand, seven hundred eighty-nine".