64121561855361 has 18 divisors (see below), whose sum is σ = 97751337607170. Its totient is φ = 40497828538176.

The previous prime is 64121561855347. The next prime is 64121561855369. The reversal of 64121561855361 is 16355816512146.

It is a happy number.

64121561855361 is a `hidden beast` number, since 6 + 4 + 1 + 2 + 15 + 6 + 18 + 553 + 61 = 666.

It can be written as a sum of positive squares in only one way, i.e., 62871514872336 + 1250046983025 = 7929156^2 + 1118055^2 .

It is not a de Polignac number, because 64121561855361 - 2¹³ = 64121561847169 is a prime.

It is a super-2 number, since 2×64121561855361² (a number of 28 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 64121561855298 and 64121561855307.

It is not an unprimeable number, because it can be changed into a prime (64121561855369) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 9867888696 + ... + 9867895193.

It is an arithmetic number, because the mean of its divisors is an integer number (5430629867065).

Almost surely, 2^{64121561855361} is an apocalyptic number.

It is an amenable number.

64121561855361 is a deficient number, since it is larger than the sum of its proper divisors (33629775751809).

64121561855361 is a wasteful number, since it uses less digits than its factorization.

64121561855361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19735783933 (or 19735783911 counting only the distinct ones).

The product of its digits is 5184000, while the sum is 54.

The spelling of 64121561855361 in words is "sixty-four trillion, one hundred twenty-one billion, five hundred sixty-one million, eight hundred fifty-five thousand, three hundred sixty-one".