81153890 has 40 divisors (see below), whose sum is σ = 157982940. Its totient is φ = 29979488.

The previous prime is 81153887. The next prime is 81153901. The reversal of 81153890 is 9835118.

It can be written as a sum of positive squares in 2 ways, for example, as 80874049 + 279841 = 8993^2 + 529^2 .

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 81153890.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 2798396 + ... + 2798424.

Almost surely, 2^81153890 is an apocalyptic number.

81153890 is a deficient number, since it is larger than the sum of its proper divisors (76829050).

81153890 is an frugal number, since it uses more digits than its factorization.

81153890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128 (or 59 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 35.

The square root of 81153890 is about 9008.5453875751. The cubic root of 81153890 is about 432.9487073598.

The spelling of 81153890 in words is "eighty-one million, one hundred fifty-three thousand, eight hundred ninety".