645487537 has 2 divisors, whose sum is σ = 645487538. Its totient is φ = 645487536.

The previous prime is 645487489. The next prime is 645487547. The reversal of 645487537 is 735784546.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 341473441 + 304014096 = 18479^2 + 17436^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645487537 is a prime.

It is not a weakly prime, because it can be changed into another prime (645487547) 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 as a sum of consecutive naturals, namely, 322743768 + 322743769.

It is an arithmetic number, because the mean of its divisors is an integer number (322743769).

Almost surely, 2^645487537 is an apocalyptic number.

It is an amenable number.

645487537 is a deficient number, since it is larger than the sum of its proper divisors (1).

645487537 is an equidigital number, since it uses as much as digits as its factorization.

645487537 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2822400, while the sum is 49.

The square root of 645487537 is about 25406.4467606157. The cubic root of 645487537 is about 864.2298989731.

The spelling of 645487537 in words is "six hundred forty-five million, four hundred eighty-seven thousand, five hundred thirty-seven".