30720181 has 2 divisors, whose sum is σ = 30720182. Its totient is φ = 30720180.

The previous prime is 30720161. The next prime is 30720199. The reversal of 30720181 is 18102703.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17514225 + 13205956 = 4185^2 + 3634^2 .

It is an emirp because it is prime and its reverse (18102703) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 30720181 - 2⁹ = 30719669 is a prime.

It is a super-2 number, since 2×30720181² = 1887459041345522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (30720161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15360090 + 15360091.

It is an arithmetic number, because the mean of its divisors is an integer number (15360091).

Almost surely, 2^30720181 is an apocalyptic number.

It is an amenable number.

30720181 is a deficient number, since it is larger than the sum of its proper divisors (1).

30720181 is an equidigital number, since it uses as much as digits as its factorization.

30720181 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 30720181 is about 5542.5789123837. The cubic root of 30720181 is about 313.1900263887.

Adding to 30720181 its reverse (18102703), we get a palindrome (48822884).

The spelling of 30720181 in words is "thirty million, seven hundred twenty thousand, one hundred eighty-one".