661101777270 has 192 divisors, whose sum is σ = 1929472634880. Its totient is φ = 159746428800.

The previous prime is 661101777269. The next prime is 661101777299. The reversal of 661101777270 is 72777101166.

661101777270 is a `hidden beast` number, since 6 + 611 + 0 + 1 + 7 + 7 + 7 + 27 + 0 = 666.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 449422635 + ... + 449424105.

It is an arithmetic number, because the mean of its divisors is an integer number (10049336640).

Almost surely, 2^661101777270 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661101777270, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (964736317440).

661101777270 is an abundant number, since it is smaller than the sum of its proper divisors (1268370857610).

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

661101777270 is a wasteful number, since it uses less digits than its factorization.

661101777270 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2276 (or 1881 counting only the distinct ones).

The product of its (nonzero) digits is 172872, while the sum is 45.

The spelling of 661101777270 in words is "six hundred sixty-one billion, one hundred one million, seven hundred seventy-seven thousand, two hundred seventy".