81499216 has 20 divisors (see below), whose sum is σ = 159305652. Its totient is φ = 40388096.

The previous prime is 81499163. The next prime is 81499219. The reversal of 81499216 is 61299418.

It can be written as a sum of positive squares in 2 ways, for example, as 18455616 + 63043600 = 4296^2 + 7940^2 .

It is a super-2 number, since 2×81499216² = 13284244417229312, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81499219) 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, 20731 + ... + 24346.

Almost surely, 2^81499216 is an apocalyptic number.

It is an amenable number.

81499216 is a deficient number, since it is larger than the sum of its proper divisors (77806436).

81499216 is a wasteful number, since it uses less digits than its factorization.

81499216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45198 (or 45192 counting only the distinct ones).

The product of its digits is 31104, while the sum is 40.

The square root of 81499216 is about 9027.6916207855. The cubic root of 81499216 is about 433.5619327700.

The spelling of 81499216 in words is "eighty-one million, four hundred ninety-nine thousand, two hundred sixteen".