1661616151551 has 24 divisors (see below), whose sum is σ = 2402246246400. Its totient is φ = 1106759457936.

The previous prime is 1661616151513. The next prime is 1661616151621. The reversal of 1661616151551 is 1551516161661.

1661616151551 is a `hidden beast` number, since 1 + 6 + 6 + 1 + 616 + 15 + 15 + 5 + 1 = 666.

It is not a de Polignac number, because 1661616151551 - 2¹⁰ = 1661616150527 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1661616151497 and 1661616151506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661616151451) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 139590466 + ... + 139602368.

It is an arithmetic number, because the mean of its divisors is an integer number (100093593600).

Almost surely, 2^{1661616151551} is an apocalyptic number.

1661616151551 is a deficient number, since it is larger than the sum of its proper divisors (740630094849).

1661616151551 is a wasteful number, since it uses less digits than its factorization.

1661616151551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24395 (or 24392 counting only the distinct ones).

The product of its digits is 162000, while the sum is 45.

The spelling of 1661616151551 in words is "one trillion, six hundred sixty-one billion, six hundred sixteen million, one hundred fifty-one thousand, five hundred fifty-one".