6561900 has 108 divisors (see below), whose sum is σ = 21529872. Its totient is φ = 1668480.

The previous prime is 6561887. The next prime is 6561911. The reversal of 6561900 is 91656.

6561900 = T₇₁₂ + T₇₁₃ + ... + T₇₃₆.

6561900 is a `hidden beast` number, since 656 + 1 + 9 + 0 + 0 = 666.

It is a super-2 number, since 2×6561900² = 86117063220000, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 20542 + ... + 20858.

Almost surely, 2^6561900 is an apocalyptic number.

6561900 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6561900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10764936).

6561900 is an abundant number, since it is smaller than the sum of its proper divisors (14967972).

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

6561900 is a wasteful number, since it uses less digits than its factorization.

6561900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 360 (or 350 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 27.

The square root of 6561900 is about 2561.6205808043. The cubic root of 6561900 is about 187.2161036990.

It can be divided in two parts, 6561 and 900, that multiplied together give a square (5904900 = 2430²).

The spelling of 6561900 in words is "six million, five hundred sixty-one thousand, nine hundred".