18870949 has 2 divisors, whose sum is σ = 18870950. Its totient is φ = 18870948.

The previous prime is 18870931. The next prime is 18870959. The reversal of 18870949 is 94907881.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18576100 + 294849 = 4310^2 + 543^2 .

It is an emirp because it is prime and its reverse (94907881) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18870949 - 2⁷ = 18870821 is a prime.

It is a super-2 number, since 2×18870949² = 712225432321202, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 18870899 and 18870908.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18870959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9435474 + 9435475.

It is an arithmetic number, because the mean of its divisors is an integer number (9435475).

Almost surely, 2^18870949 is an apocalyptic number.

It is an amenable number.

18870949 is a deficient number, since it is larger than the sum of its proper divisors (1).

18870949 is an equidigital number, since it uses as much as digits as its factorization.

18870949 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 145152, while the sum is 46.

The square root of 18870949 is about 4344.0705565172. The cubic root of 18870949 is about 266.2346517048.

The spelling of 18870949 in words is "eighteen million, eight hundred seventy thousand, nine hundred forty-nine".