6561439858 has 8 divisors (see below), whose sum is σ = 9842508720. Its totient is φ = 3280603620.

The previous prime is 6561439849. The next prime is 6561439861. The reversal of 6561439858 is 8589341656.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 6561439799 and 6561439808.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 62073 + ... + 130291.

It is an arithmetic number, because the mean of its divisors is an integer number (1230313590).

Almost surely, 2^6561439858 is an apocalyptic number.

6561439858 is a deficient number, since it is larger than the sum of its proper divisors (3281068862).

6561439858 is a wasteful number, since it uses less digits than its factorization.

6561439858 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116312.

The product of its digits is 6220800, while the sum is 55.

The square root of 6561439858 is about 81002.7151273338. The cubic root of 6561439858 is about 1872.1172752718.

The spelling of 6561439858 in words is "six billion, five hundred sixty-one million, four hundred thirty-nine thousand, eight hundred fifty-eight".