21730505893 has 2 divisors, whose sum is σ = 21730505894. Its totient is φ = 21730505892.

The previous prime is 21730505879. The next prime is 21730505959. The reversal of 21730505893 is 39850503712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12864776929 + 8865728964 = 113423^2 + 94158^2 .

It is a cyclic number.

It is not a de Polignac number, because 21730505893 - 2²⁵ = 21696951461 is a prime.

It is a super-3 number, since 3×21730505893³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21730505803) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10865252946 + 10865252947.

It is an arithmetic number, because the mean of its divisors is an integer number (10865252947).

Almost surely, 2^21730505893 is an apocalyptic number.

It is an amenable number.

21730505893 is a deficient number, since it is larger than the sum of its proper divisors (1).

21730505893 is an equidigital number, since it uses as much as digits as its factorization.

21730505893 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 226800, while the sum is 43.

The spelling of 21730505893 in words is "twenty-one billion, seven hundred thirty million, five hundred five thousand, eight hundred ninety-three".