81910490 has 8 divisors (see below), whose sum is σ = 147438900. Its totient is φ = 32764192.

The previous prime is 81910487. The next prime is 81910523. The reversal of 81910490 is 9401918.

It can be written as a sum of positive squares in 2 ways, for example, as 75463969 + 6446521 = 8687^2 + 2539^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4095515 + ... + 4095534.

Almost surely, 2^81910490 is an apocalyptic number.

81910490 is a deficient number, since it is larger than the sum of its proper divisors (65528410).

81910490 is a wasteful number, since it uses less digits than its factorization.

81910490 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8191056.

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 81910490 is about 9050.4414256985. The cubic root of 81910490 is about 434.2900119426.

The spelling of 81910490 in words is "eighty-one million, nine hundred ten thousand, four hundred ninety".