81790490 has 16 divisors (see below), whose sum is σ = 150814440. Its totient is φ = 31918080.

The previous prime is 81790477. The next prime is 81790537. The reversal of 81790490 is 9409718.

It can be written as a sum of positive squares in 4 ways, for example, as 46280809 + 35509681 = 6803^2 + 5959^2 .

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, 99335 + ... + 100154.

Almost surely, 2^81790490 is an apocalyptic number.

81790490 is a deficient number, since it is larger than the sum of its proper divisors (69023950).

81790490 is a wasteful number, since it uses less digits than its factorization.

81790490 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 199537.

The product of its (nonzero) digits is 18144, while the sum is 38.

The square root of 81790490 is about 9043.8094849460. The cubic root of 81790490 is about 434.0778280013.

The spelling of 81790490 in words is "eighty-one million, seven hundred ninety thousand, four hundred ninety".