21333367777 has 2 divisors, whose sum is σ = 21333367778. Its totient is φ = 21333367776.

The previous prime is 21333367703. The next prime is 21333367829. The reversal of 21333367777 is 77776333312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21103663441 + 229704336 = 145271^2 + 15156^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21333367777 is a prime.

It is a super-2 number, since 2×21333367777² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21333367777.

It is not a weakly prime, because it can be changed into another prime (21333367177) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10666683888 + 10666683889.

It is an arithmetic number, because the mean of its divisors is an integer number (10666683889).

Almost surely, 2^21333367777 is an apocalyptic number.

It is an amenable number.

21333367777 is a deficient number, since it is larger than the sum of its proper divisors (1).

21333367777 is an equidigital number, since it uses as much as digits as its factorization.

21333367777 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2333772, while the sum is 49.

The spelling of 21333367777 in words is "twenty-one billion, three hundred thirty-three million, three hundred sixty-seven thousand, seven hundred seventy-seven".