20731428 has 36 divisors (see below), whose sum is σ = 52922688. Its totient is φ = 6842160.

The previous prime is 20731423. The next prime is 20731429. The reversal of 20731428 is 82413702.

20731428 is a `hidden beast` number, since 207 + 31 + 428 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is not an unprimeable number, because it can be changed into a prime (20731423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 913 + ... + 6503.

Almost surely, 2^20731428 is an apocalyptic number.

It is an amenable number.

20731428 is an abundant number, since it is smaller than the sum of its proper divisors (32191260).

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

20731428 is a wasteful number, since it uses less digits than its factorization.

20731428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5704 (or 5699 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 20731428 is about 4553.1777913892. The cubic root of 20731428 is about 274.7112252413.

The spelling of 20731428 in words is "twenty million, seven hundred thirty-one thousand, four hundred twenty-eight".