30781189 has 2 divisors, whose sum is σ = 30781190. Its totient is φ = 30781188.

The previous prime is 30781187. The next prime is 30781319. The reversal of 30781189 is 98118703.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16265089 + 14516100 = 4033^2 + 3810^2 .

It is an emirp because it is prime and its reverse (98118703) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 30781189 - 2¹ = 30781187 is a prime.

Together with 30781187, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (30781183) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15390594 + 15390595.

It is an arithmetic number, because the mean of its divisors is an integer number (15390595).

Almost surely, 2^30781189 is an apocalyptic number.

It is an amenable number.

30781189 is a deficient number, since it is larger than the sum of its proper divisors (1).

30781189 is an equidigital number, since it uses as much as digits as its factorization.

30781189 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12096, while the sum is 37.

The square root of 30781189 is about 5548.0797578982. The cubic root of 30781189 is about 313.3972133477.

The spelling of 30781189 in words is "thirty million, seven hundred eighty-one thousand, one hundred eighty-nine".