6661515558456 has 192 divisors, whose sum is σ = 20766862396800. Its totient is φ = 1907852486400.

The previous prime is 6661515558353. The next prime is 6661515558461. The reversal of 6661515558456 is 6548555151666.

It is a junction number, because it is equal to n+sod(n) for n = 6661515558393 and 6661515558402.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5809455 + ... + 6860961.

It is an arithmetic number, because the mean of its divisors is an integer number (108160741650).

Almost surely, 2^{6661515558456} is an apocalyptic number.

6661515558456 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6661515558456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10383431198400).

6661515558456 is an abundant number, since it is smaller than the sum of its proper divisors (14105346838344).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6661515558456 is a wasteful number, since it uses less digits than its factorization.

6661515558456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1051970 (or 1051963 counting only the distinct ones).

The product of its digits is 129600000, while the sum is 63.

The spelling of 6661515558456 in words is "six trillion, six hundred sixty-one billion, five hundred fifteen million, five hundred fifty-eight thousand, four hundred fifty-six".