661091386164 has 48 divisors (see below), whose sum is σ = 1706479197696. Its totient is φ = 197509160800.

The previous prime is 661091386159. The next prime is 661091386237. The reversal of 661091386164 is 461683190166.

661091386164 is digitally balanced in base 7, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35260122 + ... + 35278865.

It is an arithmetic number, because the mean of its divisors is an integer number (35551649952).

Almost surely, 2^661091386164 is an apocalyptic number.

It is an amenable number.

661091386164 is an abundant number, since it is smaller than the sum of its proper divisors (1045387811532).

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

661091386164 is a wasteful number, since it uses less digits than its factorization.

661091386164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70539076 (or 70539074 counting only the distinct ones).

The product of its (nonzero) digits is 1119744, while the sum is 51.

The spelling of 661091386164 in words is "six hundred sixty-one billion, ninety-one million, three hundred eighty-six thousand, one hundred sixty-four".