21701981273 has 6 divisors (see below), whose sum is σ = 25245161946. Its totient is φ = 18601698192.

The previous prime is 21701981219. The next prime is 21701981281. The reversal of 21701981273 is 37218910712.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 15927197209 + 5774784064 = 126203^2 + 75992^2 .

It is not a de Polignac number, because 21701981273 - 2¹² = 21701977177 is a prime.

It is a super-3 number, since 3×21701981273³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21701981273.

It is not an unprimeable number, because it can be changed into a prime (21701981173) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 221448740 + ... + 221448837.

It is an arithmetic number, because the mean of its divisors is an integer number (4207526991).

Almost surely, 2^21701981273 is an apocalyptic number.

It is an amenable number.

21701981273 is a deficient number, since it is larger than the sum of its proper divisors (3543180673).

21701981273 is an equidigital number, since it uses as much as digits as its factorization.

21701981273 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 442897591 (or 442897584 counting only the distinct ones).

The product of its (nonzero) digits is 42336, while the sum is 41.

The spelling of 21701981273 in words is "twenty-one billion, seven hundred one million, nine hundred eighty-one thousand, two hundred seventy-three".