28742640 has 160 divisors (see below), whose sum is σ = 95993856. Its totient is φ = 7096320.

The previous prime is 28742629. The next prime is 28742641. The reversal of 28742640 is 4624782.

It is a super-2 number, since 2×28742640² = 1652278708339200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28742641) 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, 226257 + ... + 226383.

Almost surely, 2^28742640 is an apocalyptic number.

28742640 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 28742640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47996928).

28742640 is an abundant number, since it is smaller than the sum of its proper divisors (67251216).

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

28742640 is a wasteful number, since it uses less digits than its factorization.

28742640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 207 (or 201 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 33.

The square root of 28742640 is about 5361.2162799126. The cubic root of 28742640 is about 306.3201399808.

The spelling of 28742640 in words is "twenty-eight million, seven hundred forty-two thousand, six hundred forty".