661536330906 has 64 divisors (see below), whose sum is σ = 1531178505216. Its totient is φ = 188312544000.

The previous prime is 661536330883. The next prime is 661536330911. The reversal of 661536330906 is 609033635166.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 23131 + ... + 1150481.

It is an arithmetic number, because the mean of its divisors is an integer number (23924664144).

Almost surely, 2^661536330906 is an apocalyptic number.

661536330906 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 661536330906, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (765589252608).

661536330906 is an abundant number, since it is smaller than the sum of its proper divisors (869642174310).

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

661536330906 is a wasteful number, since it uses less digits than its factorization.

661536330906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1127907.

The product of its (nonzero) digits is 1574640, while the sum is 48.

The spelling of 661536330906 in words is "six hundred sixty-one billion, five hundred thirty-six million, three hundred thirty thousand, nine hundred six".