645487491 has 16 divisors (see below), whose sum is σ = 960727680. Its totient is φ = 382105920.

The previous prime is 645487489. The next prime is 645487537. The reversal of 645487491 is 194784546.

It is not a de Polignac number, because 645487491 - 2¹ = 645487489 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 645487491.

It is not an unprimeable number, because it can be changed into a prime (645487391) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 226026 + ... + 228863.

It is an arithmetic number, because the mean of its divisors is an integer number (60045480).

Almost surely, 2^645487491 is an apocalyptic number.

645487491 is a deficient number, since it is larger than the sum of its proper divisors (315240189).

645487491 is a wasteful number, since it uses less digits than its factorization.

645487491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 454946.

The product of its digits is 967680, while the sum is 48.

The square root of 645487491 is about 25406.4458553336. The cubic root of 645487491 is about 864.2298784436.

The spelling of 645487491 in words is "six hundred forty-five million, four hundred eighty-seven thousand, four hundred ninety-one".