20725866 has 48 divisors (see below), whose sum is σ = 51851904. Its totient is φ = 5860512.

The previous prime is 20725853. The next prime is 20725867. The reversal of 20725866 is 66852702.

20725866 is a `hidden beast` number, since 2 + 0 + 72 + 586 + 6 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 20725866.

It is not an unprimeable number, because it can be changed into a prime (20725867) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12180 + ... + 13776.

It is an arithmetic number, because the mean of its divisors is an integer number (1080248).

Almost surely, 2^20725866 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20725866, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25925952).

20725866 is an abundant number, since it is smaller than the sum of its proper divisors (31126038).

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

20725866 is a wasteful number, since it uses less digits than its factorization.

20725866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1715 (or 1712 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

The square root of 20725866 is about 4552.5669682060. The cubic root of 20725866 is about 274.6866557729.

The spelling of 20725866 in words is "twenty million, seven hundred twenty-five thousand, eight hundred sixty-six".