168611237831521 has 9 divisors (see below), whose sum is σ = 173291955894099. Its totient is φ = 164053709888184.

The previous prime is 168611237831507. The next prime is 168611237831557. The reversal of 168611237831521 is 125138732116861.

The square root of 168611237831521 is 12985039.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 150875651091025 + 17735586740496 = 12283145^2 + 4211364^2 .

It is not a de Polignac number, because 168611237831521 - 2²¹ = 168611235734369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (168611237871521) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 480270970 + ... + 480621916.

It is an arithmetic number, because the mean of its divisors is an integer number (19254661766011).

Almost surely, 2^{168611237831521} is an apocalyptic number.

168611237831521 is the 12985039-th square number.

168611237831521 is the 6492520-th centered octagonal number.

It is an amenable number.

168611237831521 is a deficient number, since it is larger than the sum of its proper divisors (4680718062578).

168611237831521 is an frugal number, since it uses more digits than its factorization.

168611237831521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 701968 (or 350984 counting only the distinct ones).

The product of its digits is 2903040, while the sum is 55.

The spelling of 168611237831521 in words is "one hundred sixty-eight trillion, six hundred eleven billion, two hundred thirty-seven million, eight hundred thirty-one thousand, five hundred twenty-one".