645449472 has 180 divisors, whose sum is σ = 2038939056. Its totient is φ = 202383360.

The previous prime is 645449471. The next prime is 645449473. The reversal of 645449472 is 274944546.

645449472 is a `hidden beast` number, since 64 + 544 + 9 + 47 + 2 = 666.

It is an interprime number because it is at equal distance from previous prime (645449471) and next prime (645449473).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645449471) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 351597 + ... + 353427.

Almost surely, 2^645449472 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 645449472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1019469528).

645449472 is an abundant number, since it is smaller than the sum of its proper divisors (1393489584).

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

645449472 is a wasteful number, since it uses less digits than its factorization.

645449472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1876 (or 1853 counting only the distinct ones).

The product of its digits is 967680, while the sum is 45.

The square root of 645449472 is about 25405.6976286816. The cubic root of 645449472 is about 864.2129104924.

The spelling of 645449472 in words is "six hundred forty-five million, four hundred forty-nine thousand, four hundred seventy-two".