81609410 has 8 divisors (see below), whose sum is σ = 146896956. Its totient is φ = 32643760.

The previous prime is 81609397. The next prime is 81609413. The reversal of 81609410 is 1490618.

It can be written as a sum of positive squares in 2 ways, for example, as 75463969 + 6145441 = 8687^2 + 2479^2 .

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

It is not an unprimeable number, because it can be changed into a prime (81609413) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4080461 + ... + 4080480.

Almost surely, 2^81609410 is an apocalyptic number.

81609410 is a deficient number, since it is larger than the sum of its proper divisors (65287546).

81609410 is a wasteful number, since it uses less digits than its factorization.

81609410 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8160948.

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 81609410 is about 9033.7926697484. The cubic root of 81609410 is about 433.7572491985.

The spelling of 81609410 in words is "eighty-one million, six hundred nine thousand, four hundred ten".