81264778 has 16 divisors (see below), whose sum is σ = 139518720. Its totient is φ = 34775856.

The previous prime is 81264763. The next prime is 81264779. The reversal of 81264778 is 87746218.

It is not an unprimeable number, because it can be changed into a prime (81264779) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6303 + ... + 14221.

It is an arithmetic number, because the mean of its divisors is an integer number (8719920).

Almost surely, 2^81264778 is an apocalyptic number.

81264778 is a deficient number, since it is larger than the sum of its proper divisors (58253942).

81264778 is a wasteful number, since it uses less digits than its factorization.

81264778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8661.

The product of its digits is 150528, while the sum is 43.

The square root of 81264778 is about 9014.6978873393. The cubic root of 81264778 is about 433.1458101176.

The spelling of 81264778 in words is "eighty-one million, two hundred sixty-four thousand, seven hundred seventy-eight".