2644243581 has 16 divisors (see below), whose sum is σ = 4035852800. Its totient is φ = 1508547888.

The previous prime is 2644243573. The next prime is 2644243583. The reversal of 2644243581 is 1853424462.

It is not a de Polignac number, because 2644243581 - 2³ = 2644243573 is a prime.

It is a super-2 number, since 2×2644243581² = 13984048231319407122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2644243583) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 88711 + ... + 114708.

It is an arithmetic number, because the mean of its divisors is an integer number (252240800).

Almost surely, 2^2644243581 is an apocalyptic number.

2644243581 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2644243581 is a deficient number, since it is larger than the sum of its proper divisors (1391609219).

2644243581 is a wasteful number, since it uses less digits than its factorization.

2644243581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204048.

The product of its digits is 184320, while the sum is 39.

The square root of 2644243581 is about 51422.2090248951. The cubic root of 2644243581 is about 1382.8247783827.

The spelling of 2644243581 in words is "two billion, six hundred forty-four million, two hundred forty-three thousand, five hundred eighty-one".