21827777 has 2 divisors, whose sum is σ = 21827778. Its totient is φ = 21827776.

The previous prime is 21827753. The next prime is 21827801. The reversal of 21827777 is 77772812.

It is a balanced prime because it is at equal distance from previous prime (21827753) and next prime (21827801).

It can be written as a sum of positive squares in only one way, i.e., 20349121 + 1478656 = 4511^2 + 1216^2 .

It is a cyclic number.

It is not a de Polignac number, because 21827777 - 2¹⁸ = 21565633 is a prime.

It is not a weakly prime, because it can be changed into another prime (21827717) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10913888 + 10913889.

It is an arithmetic number, because the mean of its divisors is an integer number (10913889).

Almost surely, 2^21827777 is an apocalyptic number.

It is an amenable number.

21827777 is a deficient number, since it is larger than the sum of its proper divisors (1).

21827777 is an equidigital number, since it uses as much as digits as its factorization.

21827777 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 76832, while the sum is 41.

The square root of 21827777 is about 4672.0206549201. The cubic root of 21827777 is about 279.4708415856.

The spelling of 21827777 in words is "twenty-one million, eight hundred twenty-seven thousand, seven hundred seventy-seven".