81423554 has 4 divisors (see below), whose sum is σ = 122135334. Its totient is φ = 40711776.

The previous prime is 81423547. The next prime is 81423571. The reversal of 81423554 is 45532418.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 45532418 = 2 ⋅22766209.

It can be written as a sum of positive squares in only one way, i.e., 81414529 + 9025 = 9023^2 + 95^2 .

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 81423554.

It is an unprimeable number.

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, 20355887 + ... + 20355890.

Almost surely, 2^81423554 is an apocalyptic number.

81423554 is a deficient number, since it is larger than the sum of its proper divisors (40711780).

81423554 is a wasteful number, since it uses less digits than its factorization.

81423554 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40711779.

The product of its digits is 19200, while the sum is 32.

The square root of 81423554 is about 9023.5000969690. The cubic root of 81423554 is about 433.4277215823.

The spelling of 81423554 in words is "eighty-one million, four hundred twenty-three thousand, five hundred fifty-four".