645907212 has 72 divisors (see below), whose sum is σ = 1671271056. Its totient is φ = 210276864.

The previous prime is 645907201. The next prime is 645907243. The reversal of 645907212 is 212709546.

645907212 is a `hidden beast` number, since 64 + 590 + 7 + 2 + 1 + 2 = 666.

It is a super-2 number, since 2×645907212² = 834392253027225888, which contains 22 as substring.

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

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, 280048 + ... + 282344.

It is an arithmetic number, because the mean of its divisors is an integer number (23212098).

Almost surely, 2^645907212 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 645907212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (835635528).

645907212 is an abundant number, since it is smaller than the sum of its proper divisors (1025363844).

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

645907212 is a wasteful number, since it uses less digits than its factorization.

645907212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2487 (or 2482 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 36.

The square root of 645907212 is about 25414.7046412112. The cubic root of 645907212 is about 864.4171564522.

The spelling of 645907212 in words is "six hundred forty-five million, nine hundred seven thousand, two hundred twelve".