27981720 has 128 divisors (see below), whose sum is σ = 100497600. Its totient is φ = 6884352.

The previous prime is 27981697. The next prime is 27981727. The reversal of 27981720 is 2718972.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27981727) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 13044 + ... + 15036.

Almost surely, 2^27981720 is an apocalyptic number.

27981720 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 27981720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (50248800).

27981720 is an abundant number, since it is smaller than the sum of its proper divisors (72515880).

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

27981720 is a wasteful number, since it uses less digits than its factorization.

27981720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2026 (or 2016 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 27981720 is about 5289.7750424758. The cubic root of 27981720 is about 303.5928008416.

The spelling of 27981720 in words is "twenty-seven million, nine hundred eighty-one thousand, seven hundred twenty".