172216681 has 16 divisors (see below), whose sum is σ = 224429184. Its totient is φ = 128242944.

The previous prime is 172216679. The next prime is 172216727. The reversal of 172216681 is 186612271.

It is a cyclic number.

It is not a de Polignac number, because 172216681 - 2¹ = 172216679 is a prime.

It is a super-2 number, since 2×172216681² = 59317170429311522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (172216081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 54115 + ... + 57208.

It is an arithmetic number, because the mean of its divisors is an integer number (14026824).

Almost surely, 2^172216681 is an apocalyptic number.

It is an amenable number.

172216681 is a deficient number, since it is larger than the sum of its proper divisors (52212503).

172216681 is a wasteful number, since it uses less digits than its factorization.

172216681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111360.

The product of its digits is 8064, while the sum is 34.

The square root of 172216681 is about 13123.1353342103. The cubic root of 172216681 is about 556.3632111278.

The spelling of 172216681 in words is "one hundred seventy-two million, two hundred sixteen thousand, six hundred eighty-one".