645920730 has 384 divisors, whose sum is σ = 2254307328. Its totient is φ = 129330432.

The previous prime is 645920719. The next prime is 645920747. The reversal of 645920730 is 37029546.

645920730 is a `hidden beast` number, since 64 + 592 + 0 + 7 + 3 + 0 = 666.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 5085927 + ... + 5086053.

It is an arithmetic number, because the mean of its divisors is an integer number (5870592).

Almost surely, 2^645920730 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645920730, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1127153664).

645920730 is an abundant number, since it is smaller than the sum of its proper divisors (1608386598).

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

645920730 is a wasteful number, since it uses less digits than its factorization.

645920730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192 (or 180 counting only the distinct ones).

The product of its (nonzero) digits is 45360, while the sum is 36.

The square root of 645920730 is about 25414.9705882183. The cubic root of 645920730 is about 864.4231867867.

The spelling of 645920730 in words is "six hundred forty-five million, nine hundred twenty thousand, seven hundred thirty".