878581981 has 4 divisors (see below), whose sum is σ = 930263292. Its totient is φ = 826900672.

The previous prime is 878581973. The next prime is 878581993. The reversal of 878581981 is 189185878.

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

It can be written as a sum of positive squares in 2 ways, for example, as 801739225 + 76842756 = 28315^2 + 8766^2 .

It is not a de Polignac number, because 878581981 - 2³ = 878581973 is a prime.

It is a super-2 number, since 2×878581981² = 1543812594675768722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (878581381) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25840630 + ... + 25840663.

It is an arithmetic number, because the mean of its divisors is an integer number (232565823).

Almost surely, 2^878581981 is an apocalyptic number.

It is an amenable number.

878581981 is a deficient number, since it is larger than the sum of its proper divisors (51681311).

878581981 is a wasteful number, since it uses less digits than its factorization.

878581981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51681310.

The product of its digits is 1290240, while the sum is 55.

The square root of 878581981 is about 29640.8836069372. The cubic root of 878581981 is about 957.7689731482.

The spelling of 878581981 in words is "eight hundred seventy-eight million, five hundred eighty-one thousand, nine hundred eighty-one".