20728902 has 8 divisors (see below), whose sum is σ = 41457816. Its totient is φ = 6909632.

The previous prime is 20728891. The next prime is 20728907. The reversal of 20728902 is 20982702.

It is a sphenic number, since it is the product of 3 distinct primes.

20728902 is an admirable number.

It is a self number, because there is not a number n which added to its sum of digits gives 20728902.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20728907) 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 3 ways as a sum of consecutive naturals, for example, 1727403 + ... + 1727414.

It is an arithmetic number, because the mean of its divisors is an integer number (5182227).

Almost surely, 2^20728902 is an apocalyptic number.

20728902 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

20728902 is a wasteful number, since it uses less digits than its factorization.

20728902 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3454822.

The product of its (nonzero) digits is 4032, while the sum is 30.

The square root of 20728902 is about 4552.9003942542. The cubic root of 20728902 is about 274.7000674838.

The spelling of 20728902 in words is "twenty million, seven hundred twenty-eight thousand, nine hundred two".