102105172521 has 81 divisors (see below), whose sum is σ = 169870167831. Its totient is φ = 59050807200.

The previous prime is 102105172451. The next prime is 102105172541. The reversal of 102105172521 is 125271501201.

The square root of 102105172521 is 319539.

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

102105172521 is a `hidden beast` number, since 1 + 0 + 21 + 0 + 51 + 72 + 521 = 666.

It can be written as a sum of positive squares in only one way, i.e., 484484121 + 101620688400 = 22011^2 + 318780^2 .

It is not a de Polignac number, because 102105172521 - 2¹⁷ = 102105041449 is a prime.

It is not an unprimeable number, because it can be changed into a prime (102105172541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 242529891 + ... + 242530311.

Almost surely, 2^102105172521 is an apocalyptic number.

102105172521 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

102105172521 is the 319539-th square number.

102105172521 is the 159770-th centered octagonal number.

It is an amenable number.

102105172521 is a deficient number, since it is larger than the sum of its proper divisors (67764995310).

102105172521 is an equidigital number, since it uses as much as digits as its factorization.

102105172521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 916 (or 458 counting only the distinct ones).

The product of its (nonzero) digits is 1400, while the sum is 27.

Adding to 102105172521 its reverse (125271501201), we get a palindrome (227376673722).

The spelling of 102105172521 in words is "one hundred two billion, one hundred five million, one hundred seventy-two thousand, five hundred twenty-one".