6541555978 has 8 divisors (see below), whose sum is σ = 9813058272. Its totient is φ = 3270536556.

The previous prime is 6541555963. The next prime is 6541555991. The reversal of 6541555978 is 8795551456.

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

It is a super-2 number, since 2×6541555978² = 85583909226615072968, which contains 22 as substring.

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, 84700 + ... + 142327.

It is an arithmetic number, because the mean of its divisors is an integer number (1226632284).

Almost surely, 2^6541555978 is an apocalyptic number.

6541555978 is a deficient number, since it is larger than the sum of its proper divisors (3271502294).

6541555978 is a wasteful number, since it uses less digits than its factorization.

6541555978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 241436.

The product of its digits is 7560000, while the sum is 55.

The square root of 6541555978 is about 80879.8861151523. The cubic root of 6541555978 is about 1870.2242649046.

The spelling of 6541555978 in words is "six billion, five hundred forty-one million, five hundred fifty-five thousand, nine hundred seventy-eight".