81490 has 16 divisors (see below), whose sum is σ = 152280. Its totient is φ = 31360.

The previous prime is 81463. The next prime is 81509. The reversal of 81490 is 9418.

81490 = T₆₀ + T₆₁ + ... + T₈₈.

It can be written as a sum of positive squares in 4 ways, for example, as 71289 + 10201 = 267^2 + 101^2 .

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 150 + ... + 430.

2⁸¹⁴⁹⁰ is an apocalyptic number.

81490 is a deficient number, since it is larger than the sum of its proper divisors (70790).

81490 is a wasteful number, since it uses less digits than its factorization.

81490 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 317.

The product of its (nonzero) digits is 288, while the sum is 22.

The square root of 81490 is about 285.4645336990. The cubic root of 81490 is about 43.3545589638.

The spelling of 81490 in words is "eighty-one thousand, four hundred ninety".