6561951 has 12 divisors (see below), whose sum is σ = 9617496. Its totient is φ = 3976720.

The previous prime is 6561943. The next prime is 6561991. The reversal of 6561951 is 1591656.

It is not a de Polignac number, because 6561951 - 2³ = 6561943 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6561911) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8676 + ... + 9401.

It is an arithmetic number, because the mean of its divisors is an integer number (801458).

Almost surely, 2^6561951 is an apocalyptic number.

6561951 is a deficient number, since it is larger than the sum of its proper divisors (3055545).

6561951 is a wasteful number, since it uses less digits than its factorization.

6561951 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18102 (or 18091 counting only the distinct ones).

The product of its digits is 8100, while the sum is 33.

The square root of 6561951 is about 2561.6305354208. The cubic root of 6561951 is about 187.2165887210.

The spelling of 6561951 in words is "six million, five hundred sixty-one thousand, nine hundred fifty-one".