645738139 has 2 divisors, whose sum is σ = 645738140. Its totient is φ = 645738138.

The previous prime is 645738103. The next prime is 645738143. The reversal of 645738139 is 931837546.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 645738139 - 2¹³ = 645729947 is a prime.

It is not a weakly prime, because it can be changed into another prime (645738239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322869069 + 322869070.

It is an arithmetic number, because the mean of its divisors is an integer number (322869070).

Almost surely, 2^645738139 is an apocalyptic number.

645738139 is a deficient number, since it is larger than the sum of its proper divisors (1).

645738139 is an equidigital number, since it uses as much as digits as its factorization.

645738139 is an evil number, because the sum of its binary digits is even.

The product of its digits is 544320, while the sum is 46.

The square root of 645738139 is about 25411.3781405102. The cubic root of 645738139 is about 864.3417264456.

The spelling of 645738139 in words is "six hundred forty-five million, seven hundred thirty-eight thousand, one hundred thirty-nine".