20866956 has 72 divisors (see below), whose sum is σ = 56527296. Its totient is φ = 5940480.

The previous prime is 20866933. The next prime is 20866969. The reversal of 20866956 is 65966802.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 37875 + ... + 38421.

Almost surely, 2^20866956 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 20866956, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28263648).

20866956 is an abundant number, since it is smaller than the sum of its proper divisors (35660340).

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

20866956 is a wasteful number, since it uses less digits than its factorization.

20866956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 599 (or 580 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 42.

The square root of 20866956 is about 4568.0363396103. The cubic root of 20866956 is about 275.3085506457.

The spelling of 20866956 in words is "twenty million, eight hundred sixty-six thousand, nine hundred fifty-six".