28161980 has 48 divisors (see below), whose sum is σ = 73737216. Its totient is φ = 8777280.

The previous prime is 28161961. The next prime is 28161997. The reversal of 28161980 is 8916182.

28161980 = T₂₃₇ + T₂₃₈ + ... + T₅₆₆.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a self number, because there is not a number n which added to its sum of digits gives 28161980.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7604 + ... + 10683.

It is an arithmetic number, because the mean of its divisors is an integer number (1536192).

Almost surely, 2^28161980 is an apocalyptic number.

28161980 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28161980 is an abundant number, since it is smaller than the sum of its proper divisors (45575236).

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

28161980 is a wasteful number, since it uses less digits than its factorization.

28161980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18314 (or 18312 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 35.

The square root of 28161980 is about 5306.7862214338. The cubic root of 28161980 is about 304.2433272297.

The spelling of 28161980 in words is "twenty-eight million, one hundred sixty-one thousand, nine hundred eighty".