28531440 has 400 divisors, whose sum is σ = 123152832. Its totient is φ = 5971968.

The previous prime is 28531427. The next prime is 28531463. The reversal of 28531440 is 4413582.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 771102 + ... + 771138.

Almost surely, 2^28531440 is an apocalyptic number.

28531440 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 28531440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (61576416).

28531440 is an abundant number, since it is smaller than the sum of its proper divisors (94621392).

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

28531440 is a wasteful number, since it uses less digits than its factorization.

28531440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86 (or 71 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 28531440 is about 5341.4829401581. The cubic root of 28531440 is about 305.5680179062.

The spelling of 28531440 in words is "twenty-eight million, five hundred thirty-one thousand, four hundred forty".