1643443461 has 48 divisors (see below), whose sum is σ = 2640193920. Its totient is φ = 976752000.

The previous prime is 1643443433. The next prime is 1643443481.

1643443461 is a `hidden beast` number, since 1 + 643 + 4 + 4 + 3 + 4 + 6 + 1 = 666.

1643443461 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1643443461 - 2²³ = 1635054853 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1643443481) 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, 1609131 + ... + 1610151.

It is an arithmetic number, because the mean of its divisors is an integer number (55004040).

Almost surely, 2^1643443461 is an apocalyptic number.

1643443461 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1643443461 is a deficient number, since it is larger than the sum of its proper divisors (996750459).

1643443461 is a wasteful number, since it uses less digits than its factorization.

1643443461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1338 (or 1335 counting only the distinct ones).

The product of its digits is 82944, while the sum is 36.

The square root of 1643443461 is about 40539.4062734027. The cubic root of 1643443461 is about 1180.0984934065.

It can be divided in two parts, 16434 and 43461, that added together give a palindrome (59895).

The spelling of 1643443461 in words is "one billion, six hundred forty-three million, four hundred forty-three thousand, four hundred sixty-one".