21642551162473 has 2 divisors, whose sum is σ = 21642551162474. Its totient is φ = 21642551162472.

The previous prime is 21642551162387. The next prime is 21642551162509. The reversal of 21642551162473 is 37426115524612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11721393017104 + 9921158145369 = 3423652^2 + 3149787^2 .

It is a cyclic number.

It is not a de Polignac number, because 21642551162473 - 2⁹ = 21642551161961 is a prime.

It is a super-3 number, since 3×21642551162473³ (a number of 41 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not a weakly prime, because it can be changed into another prime (21642501162473) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10821275581236 + 10821275581237.

It is an arithmetic number, because the mean of its divisors is an integer number (10821275581237).

Almost surely, 2^{21642551162473} is an apocalyptic number.

It is an amenable number.

21642551162473 is a deficient number, since it is larger than the sum of its proper divisors (1).

21642551162473 is an equidigital number, since it uses as much as digits as its factorization.

21642551162473 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2419200, while the sum is 49.

The spelling of 21642551162473 in words is "twenty-one trillion, six hundred forty-two billion, five hundred fifty-one million, one hundred sixty-two thousand, four hundred seventy-three".