645275550 has 24 divisors (see below), whose sum is σ = 1600283736. Its totient is φ = 172073440.

The previous prime is 645275483. The next prime is 645275639. The reversal of 645275550 is 55572546.

It is a junction number, because it is equal to n+sod(n) for n = 645275499 and 645275508.

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, 2150769 + ... + 2151068.

It is an arithmetic number, because the mean of its divisors is an integer number (66678489).

Almost surely, 2^645275550 is an apocalyptic number.

645275550 is an abundant number, since it is smaller than the sum of its proper divisors (955008186).

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

645275550 is a wasteful number, since it uses less digits than its factorization.

645275550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4301852 (or 4301847 counting only the distinct ones).

The product of its (nonzero) digits is 210000, while the sum is 39.

The square root of 645275550 is about 25402.2745044612. The cubic root of 645275550 is about 864.1352802792.

The spelling of 645275550 in words is "six hundred forty-five million, two hundred seventy-five thousand, five hundred fifty".