644620154 has 8 divisors (see below), whose sum is σ = 968023008. Its totient is φ = 321945820.

The previous prime is 644620133. The next prime is 644620159. The reversal of 644620154 is 451026446.

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

It is a self number, because there is not a number n which added to its sum of digits gives 644620154.

It is not an unprimeable number, because it can be changed into a prime (644620159) 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, 179912 + ... + 183459.

It is an arithmetic number, because the mean of its divisors is an integer number (121002876).

Almost surely, 2^644620154 is an apocalyptic number.

644620154 is a deficient number, since it is larger than the sum of its proper divisors (323402854).

644620154 is a wasteful number, since it uses less digits than its factorization.

644620154 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 364260.

The product of its (nonzero) digits is 23040, while the sum is 32.

The square root of 644620154 is about 25389.3708862587. The cubic root of 644620154 is about 863.8426184033.

The spelling of 644620154 in words is "six hundred forty-four million, six hundred twenty thousand, one hundred fifty-four".