27921709 has 2 divisors, whose sum is σ = 27921710. Its totient is φ = 27921708.

The previous prime is 27921689. The next prime is 27921739. The reversal of 27921709 is 90712972.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19053225 + 8868484 = 4365^2 + 2978^2 .

It is a cyclic number.

It is not a de Polignac number, because 27921709 - 2⁷ = 27921581 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (27921739) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13960854 + 13960855.

It is an arithmetic number, because the mean of its divisors is an integer number (13960855).

Almost surely, 2^27921709 is an apocalyptic number.

It is an amenable number.

27921709 is a deficient number, since it is larger than the sum of its proper divisors (1).

27921709 is an equidigital number, since it uses as much as digits as its factorization.

27921709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15876, while the sum is 37.

The square root of 27921709 is about 5284.0996394845. The cubic root of 27921709 is about 303.3756120543.

The spelling of 27921709 in words is "twenty-seven million, nine hundred twenty-one thousand, seven hundred nine".