81900766 has 8 divisors (see below), whose sum is σ = 123286104. Its totient is φ = 40805400.

The previous prime is 81900761. The next prime is 81900787. The reversal of 81900766 is 66700918.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81900761) 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, 71785 + ... + 72916.

It is an arithmetic number, because the mean of its divisors is an integer number (15410763).

Almost surely, 2^81900766 is an apocalyptic number.

81900766 is a deficient number, since it is larger than the sum of its proper divisors (41385338).

81900766 is a wasteful number, since it uses less digits than its factorization.

81900766 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144986.

The product of its (nonzero) digits is 18144, while the sum is 37.

The square root of 81900766 is about 9049.9041983880. The cubic root of 81900766 is about 434.2728256897.

The spelling of 81900766 in words is "eighty-one million, nine hundred thousand, seven hundred sixty-six".