21033378073 has 2 divisors, whose sum is σ = 21033378074. Its totient is φ = 21033378072.

The previous prime is 21033378029. The next prime is 21033378103. The reversal of 21033378073 is 37087333012.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19645666569 + 1387711504 = 140163^2 + 37252^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21033378073 is a prime.

It is not a weakly prime, because it can be changed into another prime (21033678073) 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, 10516689036 + 10516689037.

It is an arithmetic number, because the mean of its divisors is an integer number (10516689037).

Almost surely, 2^21033378073 is an apocalyptic number.

It is an amenable number.

21033378073 is a deficient number, since it is larger than the sum of its proper divisors (1).

21033378073 is an equidigital number, since it uses as much as digits as its factorization.

21033378073 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 63504, while the sum is 37.

The spelling of 21033378073 in words is "twenty-one billion, thirty-three million, three hundred seventy-eight thousand, seventy-three".