81490390 has 16 divisors (see below), whose sum is σ = 147446208. Its totient is φ = 32426496.

The previous prime is 81490369. The next prime is 81490393. The reversal of 81490390 is 9309418.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81490393) 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, 19182 + ... + 23041.

It is an arithmetic number, because the mean of its divisors is an integer number (9215388).

Almost surely, 2^81490390 is an apocalyptic number.

81490390 is a deficient number, since it is larger than the sum of its proper divisors (65955818).

81490390 is a wasteful number, since it uses less digits than its factorization.

81490390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42423.

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 81490390 is about 9027.2027782697. The cubic root of 81490390 is about 433.5462812667.

It can be divided in two parts, 814 and 90390, that added together give a square (91204 = 302²).

The spelling of 81490390 in words is "eighty-one million, four hundred ninety thousand, three hundred ninety".