81420754 has 4 divisors (see below), whose sum is σ = 122131134. Its totient is φ = 40710376.

The previous prime is 81420751. The next prime is 81420761. The reversal of 81420754 is 45702418.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 77528025 + 3892729 = 8805^2 + 1973^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (81420751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20355187 + ... + 20355190.

Almost surely, 2^81420754 is an apocalyptic number.

81420754 is a deficient number, since it is larger than the sum of its proper divisors (40710380).

81420754 is a wasteful number, since it uses less digits than its factorization.

81420754 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40710379.

The product of its (nonzero) digits is 8960, while the sum is 31.

The square root of 81420754 is about 9023.3449451963. The cubic root of 81420754 is about 433.4227532757.

The spelling of 81420754 in words is "eighty-one million, four hundred twenty thousand, seven hundred fifty-four".