28000020 has 96 divisors (see below), whose sum is σ = 84163968. Its totient is φ = 6930432.

The previous prime is 28000019. The next prime is 28000031. The reversal of 28000020 is 2000082.

It is a super-2 number, since 2×28000020² = 1568002240000800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 98799 + ... + 99081.

It is an arithmetic number, because the mean of its divisors is an integer number (876708).

Almost surely, 2^28000020 is an apocalyptic number.

28000020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28000020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42081984).

28000020 is an abundant number, since it is smaller than the sum of its proper divisors (56163948).

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

28000020 is a wasteful number, since it uses less digits than its factorization.

28000020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 409 (or 407 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

The square root of 28000020 is about 5291.5045119512. The cubic root of 28000020 is about 303.6589694873.

The spelling of 28000020 in words is "twenty-eight million, twenty", and thus it is an aban number and an uban number.