172218643 has 2 divisors, whose sum is σ = 172218644. Its totient is φ = 172218642.

The previous prime is 172218601. The next prime is 172218689. The reversal of 172218643 is 346812271.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 172218643 - 2²¹ = 170121491 is a prime.

It is a super-2 number, since 2×172218643² = 59318521993522898, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 172218599 and 172218608.

It is not a weakly prime, because it can be changed into another prime (172216643) 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 as a sum of consecutive naturals, namely, 86109321 + 86109322.

It is an arithmetic number, because the mean of its divisors is an integer number (86109322).

Almost surely, 2^172218643 is an apocalyptic number.

172218643 is a deficient number, since it is larger than the sum of its proper divisors (1).

172218643 is an equidigital number, since it uses as much as digits as its factorization.

172218643 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16128, while the sum is 34.

The square root of 172218643 is about 13123.2100874748. The cubic root of 172218643 is about 556.3653239322.

The spelling of 172218643 in words is "one hundred seventy-two million, two hundred eighteen thousand, six hundred forty-three".