20728770 has 48 divisors (see below), whose sum is σ = 51477120. Its totient is φ = 5341920.

The previous prime is 20728759. The next prime is 20728781. The reversal of 20728770 is 7782702.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20728759) and next prime (20728781).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 28471 + ... + 29189.

It is an arithmetic number, because the mean of its divisors is an integer number (1072440).

Almost surely, 2^20728770 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20728770, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25738560).

20728770 is an abundant number, since it is smaller than the sum of its proper divisors (30748350).

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

20728770 is a wasteful number, since it uses less digits than its factorization.

20728770 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 791 (or 760 counting only the distinct ones).

The product of its (nonzero) digits is 10976, while the sum is 33.

The square root of 20728770 is about 4552.8858979772. The cubic root of 20728770 is about 274.6994843931.

The spelling of 20728770 in words is "twenty million, seven hundred twenty-eight thousand, seven hundred seventy".