27806381 has 2 divisors, whose sum is σ = 27806382. Its totient is φ = 27806380.

The previous prime is 27806377. The next prime is 27806393. The reversal of 27806381 is 18360872.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27730756 + 75625 = 5266^2 + 275^2 .

It is a cyclic number.

It is not a de Polignac number, because 27806381 - 2² = 27806377 is a prime.

It is a super-2 number, since 2×27806381² = 1546389648634322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (27806321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13903190 + 13903191.

It is an arithmetic number, because the mean of its divisors is an integer number (13903191).

Almost surely, 2^27806381 is an apocalyptic number.

It is an amenable number.

27806381 is a deficient number, since it is larger than the sum of its proper divisors (1).

27806381 is an equidigital number, since it uses as much as digits as its factorization.

27806381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16128, while the sum is 35.

The square root of 27806381 is about 5273.1756086821. The cubic root of 27806381 is about 302.9573474873.

The spelling of 27806381 in words is "twenty-seven million, eight hundred six thousand, three hundred eighty-one".