661511101645 has 8 divisors (see below), whose sum is σ = 819420203520. Its totient is φ = 512137626960.

The previous prime is 661511101613. The next prime is 661511101661. The reversal of 661511101645 is 546101115166.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 661511101645 - 2⁵ = 661511101613 is a prime.

It is a super-3 number, since 3×661511101645³ (a number of 36 digits) contains 333 as substring.

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 7 ways as a sum of consecutive naturals, for example, 2133906625 + ... + 2133906934.

It is an arithmetic number, because the mean of its divisors is an integer number (102427525440).

Almost surely, 2^661511101645 is an apocalyptic number.

It is an amenable number.

661511101645 is a deficient number, since it is larger than the sum of its proper divisors (157909101875).

661511101645 is a wasteful number, since it uses less digits than its factorization.

661511101645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4267813595.

The product of its (nonzero) digits is 21600, while the sum is 37.

The spelling of 661511101645 in words is "six hundred sixty-one billion, five hundred eleven million, one hundred one thousand, six hundred forty-five".