81906376 has 8 divisors (see below), whose sum is σ = 153574470. Its totient is φ = 40953184.

The previous prime is 81906373. The next prime is 81906389. The reversal of 81906376 is 67360918.

It can be written as a sum of positive squares in only one way, i.e., 50836900 + 31069476 = 7130^2 + 5574^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (81906373) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5119141 + ... + 5119156.

Almost surely, 2^81906376 is an apocalyptic number.

It is an amenable number.

81906376 is a deficient number, since it is larger than the sum of its proper divisors (71668094).

81906376 is a wasteful number, since it uses less digits than its factorization.

81906376 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10238303 (or 10238299 counting only the distinct ones).

The product of its (nonzero) digits is 54432, while the sum is 40.

The square root of 81906376 is about 9050.2141411129. The cubic root of 81906376 is about 434.2827410016.

The spelling of 81906376 in words is "eighty-one million, nine hundred six thousand, three hundred seventy-six".