27991960 has 64 divisors (see below), whose sum is σ = 66420000. Its totient is φ = 10601472.

The previous prime is 27991939. The next prime is 27991967. The reversal of 27991960 is 6919972.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27991967) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 68236 + ... + 68644.

Almost surely, 2^27991960 is an apocalyptic number.

27991960 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 27991960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33210000).

27991960 is an abundant number, since it is smaller than the sum of its proper divisors (38428040).

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

27991960 is a wasteful number, since it uses less digits than its factorization.

27991960 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 508 (or 504 counting only the distinct ones).

The product of its (nonzero) digits is 61236, while the sum is 43.

The square root of 27991960 is about 5290.7428589944. The cubic root of 27991960 is about 303.6298299108.

The spelling of 27991960 in words is "twenty-seven million, nine hundred ninety-one thousand, nine hundred sixty".