6561864 has 64 divisors (see below), whose sum is σ = 19310400. Its totient is φ = 2057472.

The previous prime is 6561857. The next prime is 6561871. The reversal of 6561864 is 4681656.

It is an interprime number because it is at equal distance from previous prime (6561857) and next prime (6561871).

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2779 + ... + 4565.

It is an arithmetic number, because the mean of its divisors is an integer number (301725).

Almost surely, 2^6561864 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6561864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9655200).

6561864 is an abundant number, since it is smaller than the sum of its proper divisors (12748536).

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

6561864 is a wasteful number, since it uses less digits than its factorization.

6561864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1819 (or 1809 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 6561864 is about 2561.6135539929. The cubic root of 6561864 is about 187.2157613291.

The spelling of 6561864 in words is "six million, five hundred sixty-one thousand, eight hundred sixty-four".