81266990 has 128 divisors (see below), whose sum is σ = 190080000. Its totient is φ = 24893568.

The previous prime is 81266963. The next prime is 81266993. The reversal of 81266990 is 9966218.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81266993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1889909 + ... + 1889951.

It is an arithmetic number, because the mean of its divisors is an integer number (1485000).

Almost surely, 2^81266990 is an apocalyptic number.

81266990 is an abundant number, since it is smaller than the sum of its proper divisors (108813010).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81266990 is a wasteful number, since it uses less digits than its factorization.

81266990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 119 (or 105 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 41.

The square root of 81266990 is about 9014.8205750309. The cubic root of 81266990 is about 433.1497401098.

The spelling of 81266990 in words is "eighty-one million, two hundred sixty-six thousand, nine hundred ninety".