645447075621 has 8 divisors (see below), whose sum is σ = 860600467200. Its totient is φ = 430295867232.

The previous prime is 645447075583. The next prime is 645447075643. The reversal of 645447075621 is 126570744546.

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

It is not a de Polignac number, because 645447075621 - 2⁶ = 645447075557 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645447075421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 357705 + ... + 1191153.

It is an arithmetic number, because the mean of its divisors is an integer number (107575058400).

Almost surely, 2^645447075621 is an apocalyptic number.

It is an amenable number.

645447075621 is a deficient number, since it is larger than the sum of its proper divisors (215153391579).

645447075621 is a wasteful number, since it uses less digits than its factorization.

645447075621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1091595.

The product of its (nonzero) digits is 5644800, while the sum is 51.

The spelling of 645447075621 in words is "six hundred forty-five billion, four hundred forty-seven million, seventy-five thousand, six hundred twenty-one".