6402505644 has 18 divisors (see below), whose sum is σ = 16184111580. Its totient is φ = 2134168536.

The previous prime is 6402505633. The next prime is 6402505657. The reversal of 6402505644 is 4465052046.

6402505644 is a `hidden beast` number, since 6 + 4 + 0 + 2 + 5 + 0 + 5 + 644 = 666.

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 177847379 = 6402505644 / (6 + 4 + 0 + 2 + 5 + 0 + 5 + 6 + 4 + 4).

It is a junction number, because it is equal to n+sod(n) for n = 6402505599 and 6402505608.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 88923654 + ... + 88923725.

It is an arithmetic number, because the mean of its divisors is an integer number (899117310).

Almost surely, 2^6402505644 is an apocalyptic number.

It is an amenable number.

6402505644 is an abundant number, since it is smaller than the sum of its proper divisors (9781605936).

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

6402505644 is a wasteful number, since it uses less digits than its factorization.

6402505644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 177847389 (or 177847384 counting only the distinct ones).

The product of its (nonzero) digits is 115200, while the sum is 36.

The square root of 6402505644 is about 80015.6587425236. The cubic root of 6402505644 is about 1856.8777970238.

The spelling of 6402505644 in words is "six billion, four hundred two million, five hundred five thousand, six hundred forty-four".