27661640 has 64 divisors (see below), whose sum is σ = 65784960. Its totient is φ = 10447360.

The previous prime is 27661639. The next prime is 27661643. The reversal of 27661640 is 4616672.

It is a junction number, because it is equal to n+sod(n) for n = 27661597 and 27661606.

It is not an unprimeable number, because it can be changed into a prime (27661643) 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, 98300 + ... + 98580.

It is an arithmetic number, because the mean of its divisors is an integer number (1027890).

Almost surely, 2^27661640 is an apocalyptic number.

27661640 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 27661640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32892480).

27661640 is an abundant number, since it is smaller than the sum of its proper divisors (38123320).

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

27661640 is a wasteful number, since it uses less digits than its factorization.

27661640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 422 (or 418 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 32.

The square root of 27661640 is about 5259.4334295625. The cubic root of 27661640 is about 302.4307698503.

It can be divided in two parts, 276 and 61640, that added together give a palindrome (61916).

The spelling of 27661640 in words is "twenty-seven million, six hundred sixty-one thousand, six hundred forty".