644100220601 has 4 divisors (see below), whose sum is σ = 664877647104. Its totient is φ = 623322794100.

The previous prime is 644100220579. The next prime is 644100220619. The reversal of 644100220601 is 106022001446.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 644100220601 - 2¹⁴ = 644100204217 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644100220201) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10388713205 + ... + 10388713266.

It is an arithmetic number, because the mean of its divisors is an integer number (166219411776).

Almost surely, 2^644100220601 is an apocalyptic number.

It is an amenable number.

644100220601 is a deficient number, since it is larger than the sum of its proper divisors (20777426503).

644100220601 is a wasteful number, since it uses less digits than its factorization.

644100220601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20777426502.

The product of its (nonzero) digits is 2304, while the sum is 26.

The spelling of 644100220601 in words is "six hundred forty-four billion, one hundred million, two hundred twenty thousand, six hundred one".