28401840 has 140 divisors (see below), whose sum is σ = 99209424. Its totient is φ = 7558272.

The previous prime is 28401839. The next prime is 28401847. The reversal of 28401840 is 4810482.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (28401847) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 58077 + ... + 58563.

Almost surely, 2^28401840 is an apocalyptic number.

28401840 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 28401840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (49604712).

28401840 is an abundant number, since it is smaller than the sum of its proper divisors (70807584).

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

28401840 is an equidigital number, since it uses as much as digits as its factorization.

28401840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 518 (or 497 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 27.

The square root of 28401840 is about 5329.3376699173. The cubic root of 28401840 is about 305.1046492100.

It can be divided in two parts, 28401 and 840, that added together give a square (29241 = 171²).

The spelling of 28401840 in words is "twenty-eight million, four hundred one thousand, eight hundred forty".