6403538981 has 24 divisors (see below), whose sum is σ = 7836588000. Its totient is φ = 5209590624.

The previous prime is 6403538929. The next prime is 6403539001. The reversal of 6403538981 is 1898353046.

It is not a de Polignac number, because 6403538981 - 2¹⁰ = 6403537957 is a prime.

It is a super-2 number, since 2×6403538981² = 82010622962373036722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6403538081) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 45650 + ... + 122028.

It is an arithmetic number, because the mean of its divisors is an integer number (326524500).

Almost surely, 2^6403538981 is an apocalyptic number.

It is an amenable number.

6403538981 is a deficient number, since it is larger than the sum of its proper divisors (1433049019).

6403538981 is a wasteful number, since it uses less digits than its factorization.

6403538981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76481 (or 76474 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 47.

The square root of 6403538981 is about 80022.1155743836. The cubic root of 6403538981 is about 1856.9776890255.

The spelling of 6403538981 in words is "six billion, four hundred three million, five hundred thirty-eight thousand, nine hundred eighty-one".