30781897 has 2 divisors, whose sum is σ = 30781898. Its totient is φ = 30781896.

The previous prime is 30781873. The next prime is 30781901. The reversal of 30781897 is 79818703.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25160256 + 5621641 = 5016^2 + 2371^2 .

It is an emirp because it is prime and its reverse (79818703) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 30781897 - 2⁷ = 30781769 is a prime.

It is not a weakly prime, because it can be changed into another prime (30781697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15390948 + 15390949.

It is an arithmetic number, because the mean of its divisors is an integer number (15390949).

Almost surely, 2^30781897 is an apocalyptic number.

It is an amenable number.

30781897 is a deficient number, since it is larger than the sum of its proper divisors (1).

30781897 is an equidigital number, since it uses as much as digits as its factorization.

30781897 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 84672, while the sum is 43.

The square root of 30781897 is about 5548.1435633913. The cubic root of 30781897 is about 313.3996161520.

The spelling of 30781897 in words is "thirty million, seven hundred eighty-one thousand, eight hundred ninety-seven".