645581654 has 8 divisors (see below), whose sum is σ = 991991448. Its totient is φ = 314917840.

The previous prime is 645581653. The next prime is 645581659. The reversal of 645581654 is 456185546.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645581653) 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 in 3 ways as a sum of consecutive naturals, for example, 3936392 + ... + 3936555.

It is an arithmetic number, because the mean of its divisors is an integer number (123998931).

Almost surely, 2^645581654 is an apocalyptic number.

645581654 is a deficient number, since it is larger than the sum of its proper divisors (346409794).

645581654 is a wasteful number, since it uses less digits than its factorization.

645581654 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7872990.

The product of its digits is 576000, while the sum is 44.

The square root of 645581654 is about 25408.2989198411. The cubic root of 645581654 is about 864.2719006993.

The spelling of 645581654 in words is "six hundred forty-five million, five hundred eighty-one thousand, six hundred fifty-four".