81288446 has 4 divisors (see below), whose sum is σ = 121932672. Its totient is φ = 40644222.

The previous prime is 81288439. The next prime is 81288461. The reversal of 81288446 is 64488218.

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

It is a super-2 number, since 2×81288446² = 13215622906189832, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20322110 + ... + 20322113.

It is an arithmetic number, because the mean of its divisors is an integer number (30483168).

Almost surely, 2^81288446 is an apocalyptic number.

81288446 is a deficient number, since it is larger than the sum of its proper divisors (40644226).

81288446 is a wasteful number, since it uses less digits than its factorization.

81288446 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40644225.

The product of its digits is 98304, while the sum is 41.

The square root of 81288446 is about 9016.0105368173. The cubic root of 81288446 is about 433.1878566236.

The spelling of 81288446 in words is "eighty-one million, two hundred eighty-eight thousand, four hundred forty-six".