661511101550 has 48 divisors (see below), whose sum is σ = 1325487871680. Its totient is φ = 244170944640.

The previous prime is 661511101523. The next prime is 661511101561. The reversal of 661511101550 is 55101115166.

It is a congruent number.

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 23 ways as a sum of consecutive naturals, for example, 1857179 + ... + 2184521.

It is an arithmetic number, because the mean of its divisors is an integer number (27614330660).

Almost surely, 2^661511101550 is an apocalyptic number.

661511101550 is an abundant number, since it is smaller than the sum of its proper divisors (663976770130).

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

661511101550 is a wasteful number, since it uses less digits than its factorization.

661511101550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330477 (or 330472 counting only the distinct ones).

The product of its (nonzero) digits is 4500, while the sum is 32.

The spelling of 661511101550 in words is "six hundred sixty-one billion, five hundred eleven million, one hundred one thousand, five hundred fifty".