18981761 has 8 divisors (see below), whose sum is σ = 19223400. Its totient is φ = 18741888.

The previous prime is 18981751. The next prime is 18981773. The reversal of 18981761 is 16718981.

It can be written as a sum of positive squares in 4 ways, for example, as 6864400 + 12117361 = 2620^2 + 3481^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18981761 - 2¹⁴ = 18965377 is a prime.

It is a super-2 number, since 2×18981761² = 720614501322242, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18981731) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47615 + ... + 48011.

It is an arithmetic number, because the mean of its divisors is an integer number (2402925).

Almost surely, 2^18981761 is an apocalyptic number.

It is an amenable number.

18981761 is a deficient number, since it is larger than the sum of its proper divisors (241639).

18981761 is a wasteful number, since it uses less digits than its factorization.

18981761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 883.

The product of its digits is 24192, while the sum is 41.

The square root of 18981761 is about 4356.8062844244. The cubic root of 18981761 is about 266.7547533648.

The spelling of 18981761 in words is "eighteen million, nine hundred eighty-one thousand, seven hundred sixty-one".