28621890 has 128 divisors (see below), whose sum is σ = 87091200. Its totient is φ = 6621120.

The previous prime is 28621889. The next prime is 28621891. The reversal of 28621890 is 9812682.

28621890 is a `hidden beast` number, since 28 + 621 + 8 + 9 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (28621889) and next prime (28621891).

It is not an unprimeable number, because it can be changed into a prime (28621891) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 68101 + ... + 68519.

It is an arithmetic number, because the mean of its divisors is an integer number (680400).

Almost surely, 2^28621890 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28621890, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43545600).

28621890 is an abundant number, since it is smaller than the sum of its proper divisors (58469310).

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

28621890 is a wasteful number, since it uses less digits than its factorization.

28621890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 469 (or 463 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 28621890 is about 5349.9429903505. The cubic root of 28621890 is about 305.8905798707.

The spelling of 28621890 in words is "twenty-eight million, six hundred twenty-one thousand, eight hundred ninety".