645093961690 has 12 divisors (see below), whose sum is σ = 1161173702826. Its totient is φ = 258036568728.

The previous prime is 645093961679. The next prime is 645093961703. The reversal of 645093961690 is 96169390546.

It can be written as a sum of positive squares in only one way, i.e., 580584565521 + 64509396169 = 761961^2 + 253987^2 .

It is a super-2 number, since 2×645093961690² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2412877 + ... + 2666863.

Almost surely, 2^645093961690 is an apocalyptic number.

645093961690 is a deficient number, since it is larger than the sum of its proper divisors (516079741136).

645093961690 is an frugal number, since it uses more digits than its factorization.

645093961690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 507981 (or 253994 counting only the distinct ones).

The product of its (nonzero) digits is 9447840, while the sum is 58.

The spelling of 645093961690 in words is "six hundred forty-five billion, ninety-three million, nine hundred sixty-one thousand, six hundred ninety".