21251235073 has 2 divisors, whose sum is σ = 21251235074. Its totient is φ = 21251235072.

The previous prime is 21251235029. The next prime is 21251235079. The reversal of 21251235073 is 37053215212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10660149504 + 10591085569 = 103248^2 + 102913^2 .

It is a cyclic number.

It is not a de Polignac number, because 21251235073 - 2¹⁷ = 21251104001 is a prime.

It is a super-2 number, since 2×21251235073² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21251235079) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10625617536 + 10625617537.

It is an arithmetic number, because the mean of its divisors is an integer number (10625617537).

Almost surely, 2^21251235073 is an apocalyptic number.

It is an amenable number.

21251235073 is a deficient number, since it is larger than the sum of its proper divisors (1).

21251235073 is an equidigital number, since it uses as much as digits as its factorization.

21251235073 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12600, while the sum is 31.

The spelling of 21251235073 in words is "twenty-one billion, two hundred fifty-one million, two hundred thirty-five thousand, seventy-three".