81447802 has 4 divisors (see below), whose sum is σ = 122171706. Its totient is φ = 40723900.

The previous prime is 81447797. The next prime is 81447811. The reversal of 81447802 is 20874418.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 20874418 = 2 ⋅10437209.

It can be written as a sum of positive squares in only one way, i.e., 72573361 + 8874441 = 8519^2 + 2979^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20361949 + ... + 20361952.

Almost surely, 2^81447802 is an apocalyptic number.

81447802 is a deficient number, since it is larger than the sum of its proper divisors (40723904).

81447802 is a wasteful number, since it uses less digits than its factorization.

81447802 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40723903.

The product of its (nonzero) digits is 14336, while the sum is 34.

The square root of 81447802 is about 9024.8435997529. The cubic root of 81447802 is about 433.4707423536.

The spelling of 81447802 in words is "eighty-one million, four hundred forty-seven thousand, eight hundred two".