81406610 has 8 divisors (see below), whose sum is σ = 146531916. Its totient is φ = 32562640.

The previous prime is 81406603. The next prime is 81406613. The reversal of 81406610 is 1660418.

It can be written as a sum of positive squares in 2 ways, for example, as 79370281 + 2036329 = 8909^2 + 1427^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 81406610.

It is not an unprimeable number, because it can be changed into a prime (81406613) 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, 4070321 + ... + 4070340.

Almost surely, 2^81406610 is an apocalyptic number.

81406610 is a deficient number, since it is larger than the sum of its proper divisors (65125306).

81406610 is a wasteful number, since it uses less digits than its factorization.

81406610 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8140668.

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 81406610 is about 9022.5611663208. The cubic root of 81406610 is about 433.3976544889.

The spelling of 81406610 in words is "eighty-one million, four hundred six thousand, six hundred ten".