2661405664 has 24 divisors (see below), whose sum is σ = 5242374648. Its totient is φ = 1330008960.

The previous prime is 2661405631. The next prime is 2661405701. The reversal of 2661405664 is 4665041662.

2661405664 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 43674 + ... + 85030.

It is an arithmetic number, because the mean of its divisors is an integer number (218432277).

Almost surely, 2^2661405664 is an apocalyptic number.

It is an amenable number.

2661405664 is a deficient number, since it is larger than the sum of its proper divisors (2580968984).

2661405664 is a wasteful number, since it uses less digits than its factorization.

2661405664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43378 (or 43370 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 40.

The square root of 2661405664 is about 51588.8133610379. The cubic root of 2661405664 is about 1385.8100044474.

The spelling of 2661405664 in words is "two billion, six hundred sixty-one million, four hundred five thousand, six hundred sixty-four".