661211510065142 has 16 divisors (see below), whose sum is σ = 1047848027693760. Its totient is φ = 312413948995008.

The previous prime is 661211510065111. The next prime is 661211510065187. The reversal of 661211510065142 is 241560015112166.

It is a super-2 number, since 2×661211510065142² (a number of 30 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 661211510065142.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 121278704183 + ... + 121278709634.

It is an arithmetic number, because the mean of its divisors is an integer number (65490501730860).

Almost surely, 2^{661211510065142} is an apocalyptic number.

661211510065142 is a deficient number, since it is larger than the sum of its proper divisors (386636517628618).

661211510065142 is a wasteful number, since it uses less digits than its factorization.

661211510065142 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 242557413895.

The product of its (nonzero) digits is 86400, while the sum is 41.

The spelling of 661211510065142 in words is "six hundred sixty-one trillion, two hundred eleven billion, five hundred ten million, sixty-five thousand, one hundred forty-two".