2643694640 has 20 divisors (see below), whose sum is σ = 6146590224. Its totient is φ = 1057477824.

The previous prime is 2643694639. The next prime is 2643694649. The reversal of 2643694640 is 464963462.

It is a tau number, because it is divible by the number of its divisors (20).

It is a junction number, because it is equal to n+sod(n) for n = 2643694591 and 2643694600.

It is not an unprimeable number, because it can be changed into a prime (2643694649) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16523012 + ... + 16523171.

Almost surely, 2^2643694640 is an apocalyptic number.

2643694640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2643694640 is an abundant number, since it is smaller than the sum of its proper divisors (3502895584).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2643694640 is a wasteful number, since it uses less digits than its factorization.

2643694640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33046196 (or 33046190 counting only the distinct ones).

The product of its (nonzero) digits is 746496, while the sum is 44.

The square root of 2643694640 is about 51416.8711611276. The cubic root of 2643694640 is about 1382.7290809771.

The spelling of 2643694640 in words is "two billion, six hundred forty-three million, six hundred ninety-four thousand, six hundred forty".