27781020 has 36 divisors (see below), whose sum is σ = 84269640. Its totient is φ = 7408224.

The previous prime is 27781003. The next prime is 27781027. The reversal of 27781020 is 2018772.

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27781027) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 76990 + ... + 77349.

Almost surely, 2^27781020 is an apocalyptic number.

27781020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

27781020 is an abundant number, since it is smaller than the sum of its proper divisors (56488620).

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

27781020 is a wasteful number, since it uses less digits than its factorization.

27781020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154354 (or 154349 counting only the distinct ones).

The product of its (nonzero) digits is 1568, while the sum is 27.

The square root of 27781020 is about 5270.7703421796. The cubic root of 27781020 is about 302.8652146978.

Adding to 27781020 its reverse (2018772), we get a palindrome (29799792).

The spelling of 27781020 in words is "twenty-seven million, seven hundred eighty-one thousand, twenty".