6561972 has 72 divisors (see below), whose sum is σ = 17713696. Its totient is φ = 2122848.

The previous prime is 6561943. The next prime is 6561991. The reversal of 6561972 is 2791656.

6561972 is a `hidden beast` number, since 6 + 561 + 97 + 2 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 41718 + ... + 41874.

Almost surely, 2^6561972 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 6561972, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8856848).

6561972 is an abundant number, since it is smaller than the sum of its proper divisors (11151724).

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

6561972 is a wasteful number, since it uses less digits than its factorization.

6561972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 219 (or 205 counting only the distinct ones).

The product of its digits is 22680, while the sum is 36.

The square root of 6561972 is about 2561.6346343692. The cubic root of 6561972 is about 187.2167884352.

It can be divided in two parts, 656 and 1972, that added together give a triangular number (2628 = T₇₂).

The spelling of 6561972 in words is "six million, five hundred sixty-one thousand, nine hundred seventy-two".