645451440623 has 32 divisors (see below), whose sum is σ = 726665651712. Its totient is φ = 568383984000.

The previous prime is 645451440593. The next prime is 645451440707. The reversal of 645451440623 is 326044154546.

It is a cyclic number.

It is not a de Polignac number, because 645451440623 - 2¹² = 645451436527 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645451449623) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9463961 + ... + 9531917.

It is an arithmetic number, because the mean of its divisors is an integer number (22708301616).

Almost surely, 2^645451440623 is an apocalyptic number.

645451440623 is a deficient number, since it is larger than the sum of its proper divisors (81214211089).

645451440623 is a wasteful number, since it uses less digits than its factorization.

645451440623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68255.

The product of its (nonzero) digits is 1382400, while the sum is 44.

The spelling of 645451440623 in words is "six hundred forty-five billion, four hundred fifty-one million, four hundred forty thousand, six hundred twenty-three".