6561803 has 4 divisors (see below), whose sum is σ = 6673080. Its totient is φ = 6450528.

The previous prime is 6561791. The next prime is 6561809. The reversal of 6561803 is 3081656.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 6561803 - 2⁴ = 6561787 is a prime.

It is a super-2 number, since 2×6561803² = 86114517221618, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6561809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55550 + ... + 55667.

It is an arithmetic number, because the mean of its divisors is an integer number (1668270).

Almost surely, 2^6561803 is an apocalyptic number.

6561803 is a deficient number, since it is larger than the sum of its proper divisors (111277).

6561803 is a wasteful number, since it uses less digits than its factorization.

6561803 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111276.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 6561803 is about 2561.6016474073. The cubic root of 6561803 is about 187.2151811994.

It can be divided in two parts, 65 and 61803, that multiplied together give a triangular number (4017195 = T₂₈₃₄).

The spelling of 6561803 in words is "six million, five hundred sixty-one thousand, eight hundred three".