28861920 has 240 divisors, whose sum is σ = 108673488. Its totient is φ = 7188480.

The previous prime is 28861897. The next prime is 28861933. The reversal of 28861920 is 2916882.

It is a tau number, because it is divible by the number of its divisors (240).

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 39 ways as a sum of consecutive naturals, for example, 220255 + ... + 220385.

Almost surely, 2^28861920 is an apocalyptic number.

28861920 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 28861920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (54336744).

28861920 is an abundant number, since it is smaller than the sum of its proper divisors (79811568).

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

28861920 is a wasteful number, since it uses less digits than its factorization.

28861920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 175 (or 158 counting only the distinct ones).

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

The square root of 28861920 is about 5372.3291038431. The cubic root of 28861920 is about 306.7432910818.

The spelling of 28861920 in words is "twenty-eight million, eight hundred sixty-one thousand, nine hundred twenty".