20728635 has 16 divisors (see below), whose sum is σ = 34608384. Its totient is φ = 10574432.

The previous prime is 20728633. The next prime is 20728637. The reversal of 20728635 is 53682702.

It is an interprime number because it is at equal distance from previous prime (20728633) and next prime (20728637).

It is a cyclic number.

It is not a de Polignac number, because 20728635 - 2¹ = 20728633 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20728596 and 20728605.

It is not an unprimeable number, because it can be changed into a prime (20728633) 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, 29697 + ... + 30386.

It is an arithmetic number, because the mean of its divisors is an integer number (2163024).

Almost surely, 2^20728635 is an apocalyptic number.

20728635 is a deficient number, since it is larger than the sum of its proper divisors (13879749).

20728635 is a wasteful number, since it uses less digits than its factorization.

20728635 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60114.

The product of its (nonzero) digits is 20160, while the sum is 33.

The square root of 20728635 is about 4552.8710721917. The cubic root of 20728635 is about 274.6988880479.

The spelling of 20728635 in words is "twenty million, seven hundred twenty-eight thousand, six hundred thirty-five".