645253626352541 has 2 divisors, whose sum is σ = 645253626352542. Its totient is φ = 645253626352540.

The previous prime is 645253626352537. The next prime is 645253626352579. The reversal of 645253626352541 is 145253626352546.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 399877849326916 + 245375777025625 = 19996946^2 + 15664475^2 .

It is a cyclic number.

It is not a de Polignac number, because 645253626352541 - 2² = 645253626352537 is a prime.

It is a super-2 number, since 2×645253626352541² (a number of 30 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645253626352441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322626813176270 + 322626813176271.

It is an arithmetic number, because the mean of its divisors is an integer number (322626813176271).

Almost surely, 2^{645253626352541} is an apocalyptic number.

It is an amenable number.

645253626352541 is a deficient number, since it is larger than the sum of its proper divisors (1).

645253626352541 is an equidigital number, since it uses as much as digits as its factorization.

645253626352541 is an evil number, because the sum of its binary digits is even.

The product of its digits is 155520000, while the sum is 59.

The spelling of 645253626352541 in words is "six hundred forty-five trillion, two hundred fifty-three billion, six hundred twenty-six million, three hundred fifty-two thousand, five hundred forty-one".