27721640 has 16 divisors (see below), whose sum is σ = 62373780. Its totient is φ = 11088640.

The previous prime is 27721619. The next prime is 27721649. The reversal of 27721640 is 4612772.

It can be written as a sum of positive squares in 2 ways, for example, as 27646564 + 75076 = 5258^2 + 274^2 .

It is not an unprimeable number, because it can be changed into a prime (27721649) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 346481 + ... + 346560.

Almost surely, 2^27721640 is an apocalyptic number.

27721640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

27721640 is an abundant number, since it is smaller than the sum of its proper divisors (34652140).

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

27721640 is a wasteful number, since it uses less digits than its factorization.

27721640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 693052 (or 693048 counting only the distinct ones).

The product of its (nonzero) digits is 4704, while the sum is 29.

The square root of 27721640 is about 5265.1343762529. The cubic root of 27721640 is about 302.6492763225.

The spelling of 27721640 in words is "twenty-seven million, seven hundred twenty-one thousand, six hundred forty".