81606242 has 8 divisors (see below), whose sum is σ = 123303276. Its totient is φ = 40505152.

The previous prime is 81606223. The next prime is 81606253. The reversal of 81606242 is 24260618.

It can be written as a sum of positive squares in 2 ways, for example, as 74321641 + 7284601 = 8621^2 + 2699^2 .

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

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, 148643 + ... + 149190.

Almost surely, 2^81606242 is an apocalyptic number.

81606242 is a deficient number, since it is larger than the sum of its proper divisors (41697034).

81606242 is a wasteful number, since it uses less digits than its factorization.

81606242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 297972.

The product of its (nonzero) digits is 4608, while the sum is 29.

The square root of 81606242 is about 9033.6173264092. The cubic root of 81606242 is about 433.7516364440.

The spelling of 81606242 in words is "eighty-one million, six hundred six thousand, two hundred forty-two".