28831440 has 160 divisors (see below), whose sum is σ = 99565056. Its totient is φ = 6842880.

The previous prime is 28831433. The next prime is 28831469. The reversal of 28831440 is 4413882.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 28831398 and 28831407.

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, 176799 + ... + 176961.

Almost surely, 2^28831440 is an apocalyptic number.

28831440 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 28831440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (49782528).

28831440 is an abundant number, since it is smaller than the sum of its proper divisors (70733616).

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

28831440 is a wasteful number, since it uses less digits than its factorization.

28831440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 257 (or 251 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 30.

The square root of 28831440 is about 5369.4915960452. The cubic root of 28831440 is about 306.6352729888.

The spelling of 28831440 in words is "twenty-eight million, eight hundred thirty-one thousand, four hundred forty".