18747961 has 2 divisors, whose sum is σ = 18747962. Its totient is φ = 18747960.

The previous prime is 18747959. The next prime is 18747973. The reversal of 18747961 is 16974781.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11289600 + 7458361 = 3360^2 + 2731^2 .

It is an emirp because it is prime and its reverse (16974781) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18747961 - 2¹ = 18747959 is a prime.

Together with 18747959, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (18747161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9373980 + 9373981.

It is an arithmetic number, because the mean of its divisors is an integer number (9373981).

Almost surely, 2^18747961 is an apocalyptic number.

It is an amenable number.

18747961 is a deficient number, since it is larger than the sum of its proper divisors (1).

18747961 is an equidigital number, since it uses as much as digits as its factorization.

18747961 is an odious number, because the sum of its binary digits is odd.

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

The square root of 18747961 is about 4329.8915690811. The cubic root of 18747961 is about 265.6550118985.

The spelling of 18747961 in words is "eighteen million, seven hundred forty-seven thousand, nine hundred sixty-one".