81263994 has 32 divisors (see below), whose sum is σ = 187595136. Its totient is φ = 22987200.

The previous prime is 81263993. The next prime is 81264019. The reversal of 81263994 is 49936218.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (81263993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5337 + ... + 13820.

It is an arithmetic number, because the mean of its divisors is an integer number (5862348).

Almost surely, 2^81263994 is an apocalyptic number.

81263994 is an abundant number, since it is smaller than the sum of its proper divisors (106331142).

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

81263994 is a wasteful number, since it uses less digits than its factorization.

81263994 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19270.

The product of its digits is 93312, while the sum is 42.

The square root of 81263994 is about 9014.6544026934. The cubic root of 81263994 is about 433.1444171918.

The spelling of 81263994 in words is "eighty-one million, two hundred sixty-three thousand, nine hundred ninety-four".