645506387 has 2 divisors, whose sum is σ = 645506388. Its totient is φ = 645506386.

The previous prime is 645506383. The next prime is 645506401. The reversal of 645506387 is 783605546.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 645506387 - 2² = 645506383 is a prime.

It is not a weakly prime, because it can be changed into another prime (645506383) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322753193 + 322753194.

It is an arithmetic number, because the mean of its divisors is an integer number (322753194).

Almost surely, 2^645506387 is an apocalyptic number.

645506387 is a deficient number, since it is larger than the sum of its proper divisors (1).

645506387 is an equidigital number, since it uses as much as digits as its factorization.

645506387 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 604800, while the sum is 44.

The square root of 645506387 is about 25406.8177267441. The cubic root of 645506387 is about 864.2383115161.

The spelling of 645506387 in words is "six hundred forty-five million, five hundred six thousand, three hundred eighty-seven".