645422451 has 16 divisors (see below), whose sum is σ = 884610720. Its totient is φ = 418330880.

The previous prime is 645422431. The next prime is 645422467. The reversal of 645422451 is 154224546.

It is a cyclic number.

It is not a de Polignac number, because 645422451 - 2⁹ = 645421939 is a prime.

It is not an unprimeable number, because it can be changed into a prime (645422431) 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 15 ways as a sum of consecutive naturals, for example, 27085 + ... + 44993.

It is an arithmetic number, because the mean of its divisors is an integer number (55288170).

Almost surely, 2^645422451 is an apocalyptic number.

645422451 is a deficient number, since it is larger than the sum of its proper divisors (239188269).

645422451 is a wasteful number, since it uses less digits than its factorization.

645422451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18246.

The product of its digits is 38400, while the sum is 33.

The square root of 645422451 is about 25405.1658329561. The cubic root of 645422451 is about 864.2008505641.

Adding to 645422451 its reverse (154224546), we get a palindrome (799646997).

The spelling of 645422451 in words is "six hundred forty-five million, four hundred twenty-two thousand, four hundred fifty-one".