28400020 has 48 divisors (see below), whose sum is σ = 65536128. Its totient is φ = 10252160.

The previous prime is 28400017. The next prime is 28400033. The reversal of 28400020 is 2000482.

It is a super-2 number, since 2×28400020² = 1613122272000800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 28399967 and 28400003.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36354 + ... + 37126.

It is an arithmetic number, because the mean of its divisors is an integer number (1365336).

Almost surely, 2^28400020 is an apocalyptic number.

28400020 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 28400020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32768064).

28400020 is an abundant number, since it is smaller than the sum of its proper divisors (37136108).

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

28400020 is a wasteful number, since it uses less digits than its factorization.

28400020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 960 (or 958 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 28400020 is about 5329.1669142559. The cubic root of 28400020 is about 305.0981319993.

The spelling of 28400020 in words is "twenty-eight million, four hundred thousand, twenty".