172216305 has 12 divisors (see below), whose sum is σ = 298508340. Its totient is φ = 91848672.

The previous prime is 172216259. The next prime is 172216313. The reversal of 172216305 is 503612271.

It is a happy number.

172216305 is a `hidden beast` number, since 1 + 7 + 2 + 21 + 630 + 5 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 103856481 + 68359824 = 10191^2 + 8268^2 .

It is not a de Polignac number, because 172216305 - 2¹⁵ = 172183537 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1913470 + ... + 1913559.

It is an arithmetic number, because the mean of its divisors is an integer number (24875695).

Almost surely, 2^172216305 is an apocalyptic number.

172216305 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

172216305 is a deficient number, since it is larger than the sum of its proper divisors (126292035).

172216305 is a wasteful number, since it uses less digits than its factorization.

172216305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3827040 (or 3827037 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 27.

The square root of 172216305 is about 13123.1210083577. The cubic root of 172216305 is about 556.3628062257.

Adding to 172216305 its reverse (503612271), we get a palindrome (675828576).

The spelling of 172216305 in words is "one hundred seventy-two million, two hundred sixteen thousand, three hundred five".