645871395 has 128 divisors (see below), whose sum is σ = 1264564224. Its totient is φ = 278175744.

The previous prime is 645871381. The next prime is 645871399. The reversal of 645871395 is 593178546.

It is a Cunningham number, because it is equal to 25414²-1.

It is not a de Polignac number, because 645871395 - 2²⁶ = 578762531 is a prime.

It is not an unprimeable number, because it can be changed into a prime (645871399) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 3278437 + ... + 3278633.

It is an arithmetic number, because the mean of its divisors is an integer number (9879408).

Almost surely, 2^645871395 is an apocalyptic number.

645871395 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

645871395 is a deficient number, since it is larger than the sum of its proper divisors (618692829).

645871395 is a wasteful number, since it uses less digits than its factorization.

645871395 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 301.

The product of its digits is 907200, while the sum is 48.

The square root of 645871395 is about 25413.9999803258. Note that the first 4 decimals coincide. The cubic root of 645871395 is about 864.4011782018.

The spelling of 645871395 in words is "six hundred forty-five million, eight hundred seventy-one thousand, three hundred ninety-five".