21536777 has 2 divisors, whose sum is σ = 21536778. Its totient is φ = 21536776.

The previous prime is 21536771. The next prime is 21536791. The reversal of 21536777 is 77763512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16801801 + 4734976 = 4099^2 + 2176^2 .

It is a cyclic number.

It is not a de Polignac number, because 21536777 - 2⁴ = 21536761 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21536777.

It is not a weakly prime, because it can be changed into another prime (21536771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10768388 + 10768389.

It is an arithmetic number, because the mean of its divisors is an integer number (10768389).

Almost surely, 2^21536777 is an apocalyptic number.

It is an amenable number.

21536777 is a deficient number, since it is larger than the sum of its proper divisors (1).

21536777 is an equidigital number, since it uses as much as digits as its factorization.

21536777 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 61740, while the sum is 38.

The square root of 21536777 is about 4640.7733191786. The cubic root of 21536777 is about 278.2233467290.

The spelling of 21536777 in words is "twenty-one million, five hundred thirty-six thousand, seven hundred seventy-seven".