28971540 has 96 divisors (see below), whose sum is σ = 97090560. Its totient is φ = 7129728.

The previous prime is 28971533. The next prime is 28971541. The reversal of 28971540 is 4517982.

28971540 is a `hidden beast` number, since 28 + 97 + 1 + 540 = 666.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 28971495 and 28971504.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28971541) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4957 + ... + 9083.

It is an arithmetic number, because the mean of its divisors is an integer number (1011360).

Almost surely, 2^28971540 is an apocalyptic number.

28971540 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 28971540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48545280).

28971540 is an abundant number, since it is smaller than the sum of its proper divisors (68119020).

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

28971540 is a wasteful number, since it uses less digits than its factorization.

28971540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4158 (or 4150 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The square root of 28971540 is about 5382.5217138438. The cubic root of 28971540 is about 307.1311460677.

The spelling of 28971540 in words is "twenty-eight million, nine hundred seventy-one thousand, five hundred forty".