645640933337 has 4 divisors (see below), whose sum is σ = 645708036480. Its totient is φ = 645573830196.

The previous prime is 645640933319. The next prime is 645640933403. The reversal of 645640933337 is 733339046546.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 733339046546 = 2 ⋅366669523273.

It is a cyclic number.

It is not a de Polignac number, because 645640933337 - 2¹⁶ = 645640867801 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645640933037) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33537137 + ... + 33556382.

It is an arithmetic number, because the mean of its divisors is an integer number (161427009120).

Almost surely, 2^645640933337 is an apocalyptic number.

It is an amenable number.

645640933337 is a deficient number, since it is larger than the sum of its proper divisors (67103143).

645640933337 is an equidigital number, since it uses as much as digits as its factorization.

645640933337 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67103142.

The product of its (nonzero) digits is 14696640, while the sum is 53.

The spelling of 645640933337 in words is "six hundred forty-five billion, six hundred forty million, nine hundred thirty-three thousand, three hundred thirty-seven".