645120451550 has 12 divisors (see below), whose sum is σ = 1199924039976. Its totient is φ = 258048180600.

The previous prime is 645120451531. The next prime is 645120451561. The reversal of 645120451550 is 55154021546.

It is a hoax number, since the sum of its digits (38) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is a congruent number.

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, 6451204466 + ... + 6451204565.

It is an arithmetic number, because the mean of its divisors is an integer number (99993669998).

Almost surely, 2^645120451550 is an apocalyptic number.

645120451550 is a deficient number, since it is larger than the sum of its proper divisors (554803588426).

645120451550 is a wasteful number, since it uses less digits than its factorization.

645120451550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12902409043 (or 12902409038 counting only the distinct ones).

The product of its (nonzero) digits is 120000, while the sum is 38.

The spelling of 645120451550 in words is "six hundred forty-five billion, one hundred twenty million, four hundred fifty-one thousand, five hundred fifty".