6561881654 has 16 divisors (see below), whose sum is σ = 10095802416. Its totient is φ = 3196819200.

The previous prime is 6561881653. The next prime is 6561881659. The reversal of 6561881654 is 4561881656.

It is a super-2 number, since 2×6561881654² = 86116581682203551432, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6561881653) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13694 + ... + 115374.

It is an arithmetic number, because the mean of its divisors is an integer number (630987651).

Almost surely, 2^6561881654 is an apocalyptic number.

6561881654 is a deficient number, since it is larger than the sum of its proper divisors (3533920762).

6561881654 is a wasteful number, since it uses less digits than its factorization.

6561881654 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102511.

The product of its digits is 1382400, while the sum is 50.

The square root of 6561881654 is about 81005.4421258226. The cubic root of 6561881654 is about 1872.1592922366.

The spelling of 6561881654 in words is "six billion, five hundred sixty-one million, eight hundred eighty-one thousand, six hundred fifty-four".