645819550 has 48 divisors (see below), whose sum is σ = 1230055200. Its totient is φ = 252201600.

The previous prime is 645819547. The next prime is 645819563. The reversal of 645819550 is 55918546.

It is a junction number, because it is equal to n+sod(n) for n = 645819497 and 645819506.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 386116 + ... + 387784.

It is an arithmetic number, because the mean of its divisors is an integer number (25626150).

Almost surely, 2^645819550 is an apocalyptic number.

645819550 is a deficient number, since it is larger than the sum of its proper divisors (584235650).

645819550 is a wasteful number, since it uses less digits than its factorization.

645819550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1861 (or 1856 counting only the distinct ones).

The product of its (nonzero) digits is 216000, while the sum is 43.

The square root of 645819550 is about 25412.9799511982. The cubic root of 645819550 is about 864.3780486858.

The spelling of 645819550 in words is "six hundred forty-five million, eight hundred nineteen thousand, five hundred fifty".