81429776 has 10 divisors (see below), whose sum is σ = 157770222. Its totient is φ = 40714880.

The previous prime is 81429773. The next prime is 81429781. The reversal of 81429776 is 67792418.

It can be written as a sum of positive squares in only one way, i.e., 50069776 + 31360000 = 7076^2 + 5600^2 .

It is not an unprimeable number, because it can be changed into a prime (81429773) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2544665 + ... + 2544696.

Almost surely, 2^81429776 is an apocalyptic number.

It is an amenable number.

81429776 is a deficient number, since it is larger than the sum of its proper divisors (76340446).

81429776 is a wasteful number, since it uses less digits than its factorization.

81429776 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5089369 (or 5089363 counting only the distinct ones).

The product of its digits is 169344, while the sum is 44.

The square root of 81429776 is about 9023.8448568224. The cubic root of 81429776 is about 433.4387614615.

The spelling of 81429776 in words is "eighty-one million, four hundred twenty-nine thousand, seven hundred seventy-six".