6444540261 has 48 divisors (see below), whose sum is σ = 9659104000. Its totient is φ = 4138542720.

The previous prime is 6444540257. The next prime is 6444540281. The reversal of 6444540261 is 1620454446.

6444540261 is a `hidden beast` number, since 644 + 4 + 5 + 4 + 0 + 2 + 6 + 1 = 666.

It is not a de Polignac number, because 6444540261 - 2² = 6444540257 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6444540281) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 6028035 + ... + 6029103.

Almost surely, 2^6444540261 is an apocalyptic number.

6444540261 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

It is an amenable number.

6444540261 is a deficient number, since it is larger than the sum of its proper divisors (3214563739).

6444540261 is a wasteful number, since it uses less digits than its factorization.

6444540261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1354 (or 1351 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 36.

The square root of 6444540261 is about 80277.8939746179. The cubic root of 6444540261 is about 1860.9326132969.

The spelling of 6444540261 in words is "six billion, four hundred forty-four million, five hundred forty thousand, two hundred sixty-one".