28081980 has 36 divisors (see below), whose sum is σ = 85182552. Its totient is φ = 7488480.

The previous prime is 28081979. The next prime is 28081993. The reversal of 28081980 is 8918082.

It is a tau number, because it is divible by the number of its divisors (36).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 77826 + ... + 78185.

It is an arithmetic number, because the mean of its divisors is an integer number (2366182).

Almost surely, 2^28081980 is an apocalyptic number.

28081980 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28081980 is an abundant number, since it is smaller than the sum of its proper divisors (57100572).

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

28081980 is a wasteful number, since it uses less digits than its factorization.

28081980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156026 (or 156021 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 36.

The square root of 28081980 is about 5299.2433422141. The cubic root of 28081980 is about 303.9549650509.

The spelling of 28081980 in words is "twenty-eight million, eighty-one thousand, nine hundred eighty".