645808461 has 32 divisors (see below), whose sum is σ = 990720000. Its totient is φ = 371485440.

The previous prime is 645808459. The next prime is 645808463. The reversal of 645808461 is 164808546.

645808461 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (645808459) and next prime (645808463).

It is not a de Polignac number, because 645808461 - 2¹ = 645808459 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645808463) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19290 + ... + 40788.

It is an arithmetic number, because the mean of its divisors is an integer number (30960000).

Almost surely, 2^645808461 is an apocalyptic number.

It is an amenable number.

645808461 is a deficient number, since it is larger than the sum of its proper divisors (344911539).

645808461 is a wasteful number, since it uses less digits than its factorization.

645808461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21569.

The product of its (nonzero) digits is 184320, while the sum is 42.

The square root of 645808461 is about 25412.7617743527. The cubic root of 645808461 is about 864.3731014096.

The spelling of 645808461 in words is "six hundred forty-five million, eight hundred eight thousand, four hundred sixty-one".