81890889 has 16 divisors (see below), whose sum is σ = 111355200. Its totient is φ = 53519616.

The previous prime is 81890881. The next prime is 81890891. The reversal of 81890889 is 98809818.

It is not a de Polignac number, because 81890889 - 2³ = 81890881 is a prime.

It is a super-2 number, since 2×81890889² = 13412235402420642, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81890881) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38157 + ... + 40245.

It is an arithmetic number, because the mean of its divisors is an integer number (6959700).

Almost surely, 2^81890889 is an apocalyptic number.

It is an amenable number.

81890889 is a deficient number, since it is larger than the sum of its proper divisors (29464311).

81890889 is a wasteful number, since it uses less digits than its factorization.

81890889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2344.

The product of its (nonzero) digits is 331776, while the sum is 51.

The square root of 81890889 is about 9049.3584855502. The cubic root of 81890889 is about 434.2553676310.

The spelling of 81890889 in words is "eighty-one million, eight hundred ninety thousand, eight hundred eighty-nine".