81359316 has 42 divisors (see below), whose sum is σ = 213478202. Its totient is φ = 27118800.

The previous prime is 81359309. The next prime is 81359321. The reversal of 81359316 is 61395318.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 79388100 + 1971216 = 8910^2 + 1404^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 11035 + ... + 16866.

Almost surely, 2^81359316 is an apocalyptic number.

It is an amenable number.

81359316 is an abundant number, since it is smaller than the sum of its proper divisors (132118886).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81359316 is a wasteful number, since it uses less digits than its factorization.

81359316 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27923 (or 27906 counting only the distinct ones).

The product of its digits is 19440, while the sum is 36.

The square root of 81359316 is about 9019.9399111081. The cubic root of 81359316 is about 433.3137093020.

The spelling of 81359316 in words is "eighty-one million, three hundred fifty-nine thousand, three hundred sixteen".