81878842 has 8 divisors (see below), whose sum is σ = 122908500. Its totient is φ = 40909344.

The previous prime is 81878831. The next prime is 81878879. The reversal of 81878842 is 24887818.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 75533481 + 6345361 = 8691^2 + 2519^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 81878792 and 81878801.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11467 + ... + 17182.

Almost surely, 2^81878842 is an apocalyptic number.

81878842 is a deficient number, since it is larger than the sum of its proper divisors (41029658).

81878842 is a wasteful number, since it uses less digits than its factorization.

81878842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30080.

The product of its digits is 229376, while the sum is 46.

The square root of 81878842 is about 9048.6928337744. The cubic root of 81878842 is about 434.2340720956.

The spelling of 81878842 in words is "eighty-one million, eight hundred seventy-eight thousand, eight hundred forty-two".