18729761 has 2 divisors, whose sum is σ = 18729762. Its totient is φ = 18729760.

The previous prime is 18729757. The next prime is 18729769. The reversal of 18729761 is 16792781.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18113536 + 616225 = 4256^2 + 785^2 .

It is an emirp because it is prime and its reverse (16792781) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18729761 - 2² = 18729757 is a prime.

It is not a weakly prime, because it can be changed into another prime (18729769) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9364880 + 9364881.

It is an arithmetic number, because the mean of its divisors is an integer number (9364881).

Almost surely, 2^18729761 is an apocalyptic number.

It is an amenable number.

18729761 is a deficient number, since it is larger than the sum of its proper divisors (1).

18729761 is an equidigital number, since it uses as much as digits as its factorization.

18729761 is an evil number, because the sum of its binary digits is even.

The product of its digits is 42336, while the sum is 41.

The square root of 18729761 is about 4327.7893895152. The cubic root of 18729761 is about 265.5690205632.

The spelling of 18729761 in words is "eighteen million, seven hundred twenty-nine thousand, seven hundred sixty-one".