645824052 has 72 divisors (see below), whose sum is σ = 1691930240. Its totient is φ = 207567360.

The previous prime is 645824029. The next prime is 645824057. The reversal of 645824052 is 250428546.

It is a happy number.

645824052 is a `hidden beast` number, since 645 + 8 + 2 + 4 + 0 + 5 + 2 = 666.

It is a super-2 number, since 2×645824052² = 834177412283397408, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 645823998 and 645824016.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645824057) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 119652 + ... + 124932.

Almost surely, 2^645824052 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645824052, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (845965120).

645824052 is an abundant number, since it is smaller than the sum of its proper divisors (1046106188).

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

645824052 is a wasteful number, since it uses less digits than its factorization.

645824052 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5413 (or 5408 counting only the distinct ones).

The product of its (nonzero) digits is 76800, while the sum is 36.

The square root of 645824052 is about 25413.0685278264. The cubic root of 645824052 is about 864.3800572040.

The spelling of 645824052 in words is "six hundred forty-five million, eight hundred twenty-four thousand, fifty-two".