27721890 has 96 divisors (see below), whose sum is σ = 83566080. Its totient is φ = 6244992.

The previous prime is 27721873. The next prime is 27721901. The reversal of 27721890 is 9812772.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 49492 + ... + 50048.

It is an arithmetic number, because the mean of its divisors is an integer number (870480).

Almost surely, 2^27721890 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 27721890, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41783040).

27721890 is an abundant number, since it is smaller than the sum of its proper divisors (55844190).

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

27721890 is a wasteful number, since it uses less digits than its factorization.

27721890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 656 (or 653 counting only the distinct ones).

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

The square root of 27721890 is about 5265.1581172838. The cubic root of 27721890 is about 302.6501861063.

The spelling of 27721890 in words is "twenty-seven million, seven hundred twenty-one thousand, eight hundred ninety".