20731668 has 12 divisors (see below), whose sum is σ = 48373920. Its totient is φ = 6910552.

The previous prime is 20731663. The next prime is 20731681. The reversal of 20731668 is 86613702.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20731663) 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, 863808 + ... + 863831.

It is an arithmetic number, because the mean of its divisors is an integer number (4031160).

Almost surely, 2^20731668 is an apocalyptic number.

It is an amenable number.

20731668 is an abundant number, since it is smaller than the sum of its proper divisors (27642252).

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

20731668 is a wasteful number, since it uses less digits than its factorization.

20731668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1727646 (or 1727644 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 33.

The square root of 20731668 is about 4553.2041465324. The cubic root of 20731668 is about 274.7122853136.

It can be divided in two parts, 2073 and 1668, that added together give a triangular number (3741 = T₈₆).

The spelling of 20731668 in words is "twenty million, seven hundred thirty-one thousand, six hundred sixty-eight".