81871156 has 6 divisors (see below), whose sum is σ = 143274530. Its totient is φ = 40935576.

The previous prime is 81871129. The next prime is 81871169. The reversal of 81871156 is 65117818.

It can be written as a sum of positive squares in only one way, i.e., 68062500 + 13808656 = 8250^2 + 3716^2 .

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, 10233891 + ... + 10233898.

Almost surely, 2^81871156 is an apocalyptic number.

It is an amenable number.

81871156 is a deficient number, since it is larger than the sum of its proper divisors (61403374).

81871156 is a wasteful number, since it uses less digits than its factorization.

81871156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20467793 (or 20467791 counting only the distinct ones).

The product of its digits is 13440, while the sum is 37.

The square root of 81871156 is about 9048.2681215800. The cubic root of 81871156 is about 434.2204844278.

The spelling of 81871156 in words is "eighty-one million, eight hundred seventy-one thousand, one hundred fifty-six".