121561283507816 has 64 divisors (see below), whose sum is σ = 240330583180800. Its totient is φ = 57528740763648.

The previous prime is 121561283507773. The next prime is 121561283507843. The reversal of 121561283507816 is 618705382165121.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 103631246 + ... + 104797698.

It is an arithmetic number, because the mean of its divisors is an integer number (3755165362200).

Almost surely, 2^{121561283507816} is an apocalyptic number.

It is an amenable number.

121561283507816 is a deficient number, since it is larger than the sum of its proper divisors (118769299672984).

121561283507816 is a wasteful number, since it uses less digits than its factorization.

121561283507816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1172418 (or 1172414 counting only the distinct ones).

The product of its (nonzero) digits is 4838400, while the sum is 56.

The spelling of 121561283507816 in words is "one hundred twenty-one trillion, five hundred sixty-one billion, two hundred eighty-three million, five hundred seven thousand, eight hundred sixteen".