644260101 has 32 divisors (see below), whose sum is σ = 947189376. Its totient is φ = 387840000.

The previous prime is 644260091. The next prime is 644260109. The reversal of 644260101 is 101062446.

It is not a de Polignac number, because 644260101 - 2²³ = 635871493 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644260109) 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, 125026 + ... + 130076.

It is an arithmetic number, because the mean of its divisors is an integer number (29599668).

Almost surely, 2^644260101 is an apocalyptic number.

644260101 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

It is an amenable number.

644260101 is a deficient number, since it is larger than the sum of its proper divisors (302929275).

644260101 is a wasteful number, since it uses less digits than its factorization.

644260101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5173.

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 644260101 is about 25382.2792711766. The cubic root of 644260101 is about 863.6817551668.

The spelling of 644260101 in words is "six hundred forty-four million, two hundred sixty thousand, one hundred one".