645143123550 has 24 divisors (see below), whose sum is σ = 1599954946776. Its totient is φ = 172038166240.

The previous prime is 645143123543. The next prime is 645143123561. The reversal of 645143123550 is 55321341546.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 645143123499 and 645143123508.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2150476929 + ... + 2150477228.

It is an arithmetic number, because the mean of its divisors is an integer number (66664789449).

Almost surely, 2^645143123550 is an apocalyptic number.

645143123550 is an abundant number, since it is smaller than the sum of its proper divisors (954811823226).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645143123550 is a wasteful number, since it uses less digits than its factorization.

645143123550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4300954172 (or 4300954167 counting only the distinct ones).

The product of its (nonzero) digits is 216000, while the sum is 39.

The spelling of 645143123550 in words is "six hundred forty-five billion, one hundred forty-three million, one hundred twenty-three thousand, five hundred fifty".