30841981 has 2 divisors, whose sum is σ = 30841982. Its totient is φ = 30841980.

The previous prime is 30841973. The next prime is 30841991. The reversal of 30841981 is 18914803.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 23328900 + 7513081 = 4830^2 + 2741^2 .

It is an emirp because it is prime and its reverse (18914803) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 30841981 - 2³ = 30841973 is a prime.

It is a super-2 number, since 2×30841981² = 1902455584008722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (30841991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15420990 + 15420991.

It is an arithmetic number, because the mean of its divisors is an integer number (15420991).

Almost surely, 2^30841981 is an apocalyptic number.

It is an amenable number.

30841981 is a deficient number, since it is larger than the sum of its proper divisors (1).

30841981 is an equidigital number, since it uses as much as digits as its factorization.

30841981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6912, while the sum is 34.

The square root of 30841981 is about 5553.5557078326. Note that the first 3 decimals coincide. The cubic root of 30841981 is about 313.6033946263.

The spelling of 30841981 in words is "thirty million, eight hundred forty-one thousand, nine hundred eighty-one".