645775607381 has 8 divisors (see below), whose sum is σ = 659331368640. Its totient is φ = 632347130592.

The previous prime is 645775607369. The next prime is 645775607401. The reversal of 645775607381 is 183706577546.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 645775607381 - 2³⁰ = 644701865557 is a prime.

It is a super-2 number, since 2×645775607381² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 645775607381.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645775607311) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31810865 + ... + 31831158.

It is an arithmetic number, because the mean of its divisors is an integer number (82416421080).

Almost surely, 2^645775607381 is an apocalyptic number.

It is an amenable number.

645775607381 is a deficient number, since it is larger than the sum of its proper divisors (13555761259).

645775607381 is a wasteful number, since it uses less digits than its factorization.

645775607381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63642235.

The product of its (nonzero) digits is 29635200, while the sum is 59.

The spelling of 645775607381 in words is "six hundred forty-five billion, seven hundred seventy-five million, six hundred seven thousand, three hundred eighty-one".