20671956 has 48 divisors (see below), whose sum is σ = 53865280. Its totient is φ = 6855840.

The previous prime is 20671939. The next prime is 20671957. The reversal of 20671956 is 65917602.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 20671956.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20671957) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29571 + ... + 30261.

Almost surely, 2^20671956 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20671956, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26932640).

20671956 is an abundant number, since it is smaller than the sum of its proper divisors (33193324).

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

20671956 is a wasteful number, since it uses less digits than its factorization.

20671956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 981 (or 973 counting only the distinct ones).

The product of its (nonzero) digits is 22680, while the sum is 36.

The square root of 20671956 is about 4546.6422775494. The cubic root of 20671956 is about 274.4482867139.

The spelling of 20671956 in words is "twenty million, six hundred seventy-one thousand, nine hundred fifty-six".