28161900 has 216 divisors, whose sum is σ = 99524880. Its totient is φ = 6612480.

The previous prime is 28161899. The next prime is 28161901. The reversal of 28161900 is 916182.

It is an interprime number because it is at equal distance from previous prime (28161899) and next prime (28161901).

It is a super-2 number, since 2×28161900² = 1586185223220000, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (28161901) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 339259 + ... + 339341.

Almost surely, 2^28161900 is an apocalyptic number.

28161900 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 28161900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (49762440).

28161900 is an abundant number, since it is smaller than the sum of its proper divisors (71362980).

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

28161900 is a wasteful number, since it uses less digits than its factorization.

28161900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145 (or 135 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 28161900 is about 5306.7786839099. The cubic root of 28161900 is about 304.2430391404.

The spelling of 28161900 in words is "twenty-eight million, one hundred sixty-one thousand, nine hundred".