20956240 has 80 divisors (see below), whose sum is σ = 54371520. Its totient is φ = 7464960.

The previous prime is 20956211. The next prime is 20956261. The reversal of 20956240 is 4265902.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 20956199 and 20956208.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25435 + ... + 26245.

It is an arithmetic number, because the mean of its divisors is an integer number (679644).

Almost surely, 2^20956240 is an apocalyptic number.

20956240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20956240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27185760).

20956240 is an abundant number, since it is smaller than the sum of its proper divisors (33415280).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20956240 is a wasteful number, since it uses less digits than its factorization.

20956240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 860 (or 854 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 20956240 is about 4577.7985975794. The cubic root of 20956240 is about 275.7006486239.

The spelling of 20956240 in words is "twenty million, nine hundred fifty-six thousand, two hundred forty".