51661610166515 has 4 divisors (see below), whose sum is σ = 61993932199824. Its totient is φ = 41329288133208.

The previous prime is 51661610166499. The next prime is 51661610166559. The reversal of 51661610166515 is 51566101616615.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 51661610166515 - 2⁴ = 51661610166499 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5166161016647 + ... + 5166161016656.

It is an arithmetic number, because the mean of its divisors is an integer number (15498483049956).

Almost surely, 2^{51661610166515} is an apocalyptic number.

51661610166515 is a deficient number, since it is larger than the sum of its proper divisors (10332322033309).

51661610166515 is a wasteful number, since it uses less digits than its factorization.

51661610166515 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10332322033308.

The product of its (nonzero) digits is 972000, while the sum is 50.

The spelling of 51661610166515 in words is "fifty-one trillion, six hundred sixty-one billion, six hundred ten million, one hundred sixty-six thousand, five hundred fifteen".