18957997 has 2 divisors, whose sum is σ = 18957998. Its totient is φ = 18957996.

The previous prime is 18957989. The next prime is 18958013. The reversal of 18957997 is 79975981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15139881 + 3818116 = 3891^2 + 1954^2 .

It is a cyclic number.

It is not a de Polignac number, because 18957997 - 2³ = 18957989 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18997997) 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, 9478998 + 9478999.

It is an arithmetic number, because the mean of its divisors is an integer number (9478999).

Almost surely, 2^18957997 is an apocalyptic number.

It is an amenable number.

18957997 is a deficient number, since it is larger than the sum of its proper divisors (1).

18957997 is an equidigital number, since it uses as much as digits as its factorization.

18957997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1428840, while the sum is 55.

The square root of 18957997 is about 4354.0782032481. The cubic root of 18957997 is about 266.6433866830.

The spelling of 18957997 in words is "eighteen million, nine hundred fifty-seven thousand, nine hundred ninety-seven".