645321200251 has 16 divisors (see below), whose sum is σ = 840961566144. Its totient is φ = 480549464064.

The previous prime is 645321200233. The next prime is 645321200261. The reversal of 645321200251 is 152002123546.

It is a cyclic number.

It is not a de Polignac number, because 645321200251 - 2²⁷ = 645186982523 is a prime.

It is not an unprimeable number, because it can be changed into a prime (645321200221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 208570270 + ... + 208573363.

It is an arithmetic number, because the mean of its divisors is an integer number (52560097884).

Almost surely, 2^645321200251 is an apocalyptic number.

645321200251 is a deficient number, since it is larger than the sum of its proper divisors (195640365893).

645321200251 is a wasteful number, since it uses less digits than its factorization.

645321200251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 417143670.

The product of its (nonzero) digits is 14400, while the sum is 31.

Adding to 645321200251 its reverse (152002123546), we get a palindrome (797323323797).

The spelling of 645321200251 in words is "six hundred forty-five billion, three hundred twenty-one million, two hundred thousand, two hundred fifty-one".