645246251 has 8 divisors (see below), whose sum is σ = 731453520. Its totient is φ = 564263712.

The previous prime is 645246223. The next prime is 645246253. The reversal of 645246251 is 152642546.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 645246251 - 2⁶ = 645246187 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645246253) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1305920 + ... + 1306413.

It is an arithmetic number, because the mean of its divisors is an integer number (91431690).

Almost surely, 2^645246251 is an apocalyptic number.

645246251 is a deficient number, since it is larger than the sum of its proper divisors (86207269).

645246251 is a wasteful number, since it uses less digits than its factorization.

645246251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2612365.

The product of its digits is 57600, while the sum is 35.

The square root of 645246251 is about 25401.6977975883. The cubic root of 645246251 is about 864.1222012761.

Adding to 645246251 its reverse (152642546), we get a palindrome (797888797).

The spelling of 645246251 in words is "six hundred forty-five million, two hundred forty-six thousand, two hundred fifty-one".