21062761 has 2 divisors, whose sum is σ = 21062762. Its totient is φ = 21062760.

The previous prime is 21062759. The next prime is 21062801. The reversal of 21062761 is 16726012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18974736 + 2088025 = 4356^2 + 1445^2 .

It is a cyclic number.

It is not a de Polignac number, because 21062761 - 2¹ = 21062759 is a prime.

Together with 21062759, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21962761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10531380 + 10531381.

It is an arithmetic number, because the mean of its divisors is an integer number (10531381).

Almost surely, 2^21062761 is an apocalyptic number.

It is an amenable number.

21062761 is a deficient number, since it is larger than the sum of its proper divisors (1).

21062761 is an equidigital number, since it uses as much as digits as its factorization.

21062761 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 21062761 is about 4589.4183727353. The cubic root of 21062761 is about 276.1669900669.

Adding to 21062761 its reverse (16726012), we get a palindrome (37788773).

The spelling of 21062761 in words is "twenty-one million, sixty-two thousand, seven hundred sixty-one".