18969881 has 8 divisors (see below), whose sum is σ = 21706944. Its totient is φ = 16239600.

The previous prime is 18969877. The next prime is 18969901. The reversal of 18969881 is 18896981.

It is a happy number.

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 18969881 - 2² = 18969877 is a prime.

It is a super-2 number, since 2×18969881² = 719712770308322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (18969781) 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 in 7 ways as a sum of consecutive naturals, for example, 8066 + ... + 10148.

It is an arithmetic number, because the mean of its divisors is an integer number (2713368).

Almost surely, 2^18969881 is an apocalyptic number.

It is an amenable number.

18969881 is a deficient number, since it is larger than the sum of its proper divisors (2737063).

18969881 is a wasteful number, since it uses less digits than its factorization.

18969881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3391.

The product of its digits is 248832, while the sum is 50.

The square root of 18969881 is about 4355.4426870296. The cubic root of 18969881 is about 266.6990910226.

Subtracting from 18969881 its reverse (18896981), we obtain a square (72900 = 270²).

The spelling of 18969881 in words is "eighteen million, nine hundred sixty-nine thousand, eight hundred eighty-one".