645943404349546 has 4 divisors (see below), whose sum is σ = 968915106524322. Its totient is φ = 322971702174772.

The previous prime is 645943404349541. The next prime is 645943404349627.

645943404349546 is nontrivially palindromic in base 10.

645943404349546 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 414126366509025 + 231817037840521 = 20350095^2 + 15225539^2 .

It is a super-2 number, since 2×645943404349546² (a number of 30 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (645943404349541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161485851087385 + ... + 161485851087388.

Almost surely, 2^{645943404349546} is an apocalyptic number.

645943404349546 is a deficient number, since it is larger than the sum of its proper divisors (322971702174776).

645943404349546 is a wasteful number, since it uses less digits than its factorization.

645943404349546 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322971702174775.

The product of its (nonzero) digits is 2687385600, while the sum is 70.

The spelling of 645943404349546 in words is "six hundred forty-five trillion, nine hundred forty-three billion, four hundred four million, three hundred forty-nine thousand, five hundred forty-six".