665026405501 has 2 divisors, whose sum is σ = 665026405502. Its totient is φ = 665026405500.

The previous prime is 665026405499. The next prime is 665026405529. The reversal of 665026405501 is 105504620566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 621834759225 + 43191646276 = 788565^2 + 207826^2 .

It is a cyclic number.

It is not a de Polignac number, because 665026405501 - 2¹ = 665026405499 is a prime.

It is a super-2 number, since 2×665026405501² (a number of 24 digits) contains 22 as substring.

Together with 665026405499, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (665026402501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332513202750 + 332513202751.

It is an arithmetic number, because the mean of its divisors is an integer number (332513202751).

Almost surely, 2^665026405501 is an apocalyptic number.

It is an amenable number.

665026405501 is a deficient number, since it is larger than the sum of its proper divisors (1).

665026405501 is an equidigital number, since it uses as much as digits as its factorization.

665026405501 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 216000, while the sum is 40.

The spelling of 665026405501 in words is "six hundred sixty-five billion, twenty-six million, four hundred five thousand, five hundred one".