21214637761 has 2 divisors, whose sum is σ = 21214637762. Its totient is φ = 21214637760.

The previous prime is 21214637747. The next prime is 21214637783. The reversal of 21214637761 is 16773641212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20954299536 + 260338225 = 144756^2 + 16135^2 .

It is a cyclic number.

It is not a de Polignac number, because 21214637761 - 2¹⁷ = 21214506689 is a prime.

It is not a weakly prime, because it can be changed into another prime (21214634761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10607318880 + 10607318881.

It is an arithmetic number, because the mean of its divisors is an integer number (10607318881).

Almost surely, 2^21214637761 is an apocalyptic number.

It is an amenable number.

21214637761 is a deficient number, since it is larger than the sum of its proper divisors (1).

21214637761 is an equidigital number, since it uses as much as digits as its factorization.

21214637761 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 84672, while the sum is 40.

The spelling of 21214637761 in words is "twenty-one billion, two hundred fourteen million, six hundred thirty-seven thousand, seven hundred sixty-one".