645506401 has 2 divisors, whose sum is σ = 645506402. Its totient is φ = 645506400.

The previous prime is 645506387. The next prime is 645506461. The reversal of 645506401 is 104605546.

645506401 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 541772176 + 103734225 = 23276^2 + 10185^2 .

It is a cyclic number.

It is not a de Polignac number, because 645506401 - 2¹³ = 645498209 is a prime.

It is not a weakly prime, because it can be changed into another prime (645506461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322753200 + 322753201.

It is an arithmetic number, because the mean of its divisors is an integer number (322753201).

Almost surely, 2^645506401 is an apocalyptic number.

It is an amenable number.

645506401 is a deficient number, since it is larger than the sum of its proper divisors (1).

645506401 is an equidigital number, since it uses as much as digits as its factorization.

645506401 is an odious number, because the sum of its binary digits is odd.

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

The square root of 645506401 is about 25406.8180022607. The cubic root of 645506401 is about 864.2383177641.

The spelling of 645506401 in words is "six hundred forty-five million, five hundred six thousand, four hundred one".