661511101671 has 64 divisors (see below), whose sum is σ = 1141158707200. Its totient is φ = 370930386528.

The previous prime is 661511101661. The next prime is 661511101679. The reversal of 661511101671 is 176101115166.

It is a happy number.

661511101671 is a `hidden beast` number, since 6 + 61 + 511 + 1 + 0 + 16 + 71 = 666.

It is not a de Polignac number, because 661511101671 - 2⁹ = 661511101159 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661511101679) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2297850 + ... + 2569656.

It is an arithmetic number, because the mean of its divisors is an integer number (17830604800).

Almost surely, 2^661511101671 is an apocalyptic number.

661511101671 is a deficient number, since it is larger than the sum of its proper divisors (479647605529).

661511101671 is a wasteful number, since it uses less digits than its factorization.

661511101671 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 272065 (or 272059 counting only the distinct ones).

The product of its (nonzero) digits is 7560, while the sum is 36.

The spelling of 661511101671 in words is "six hundred sixty-one billion, five hundred eleven million, one hundred one thousand, six hundred seventy-one".