81590890 has 16 divisors (see below), whose sum is σ = 153249408. Its totient is φ = 31217296.

The previous prime is 81590863. The next prime is 81590897. The reversal of 81590890 is 9809518.

It is not an unprimeable number, because it can be changed into a prime (81590897) 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, 177142 + ... + 177601.

It is an arithmetic number, because the mean of its divisors is an integer number (9578088).

Almost surely, 2^81590890 is an apocalyptic number.

81590890 is a deficient number, since it is larger than the sum of its proper divisors (71658518).

81590890 is a wasteful number, since it uses less digits than its factorization.

81590890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 354773.

The product of its (nonzero) digits is 25920, while the sum is 40.

The square root of 81590890 is about 9032.7675714589. The cubic root of 81590890 is about 433.7244352048.

The spelling of 81590890 in words is "eighty-one million, five hundred ninety thousand, eight hundred ninety".