81447237 has 12 divisors (see below), whose sum is σ = 117749164. Its totient is φ = 54250560.

The previous prime is 81447217. The next prime is 81447239. The reversal of 81447237 is 73274418.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 32251041 + 49196196 = 5679^2 + 7014^2 .

It is not a de Polignac number, because 81447237 - 2¹⁶ = 81381701 is a prime.

It is a Duffinian number.

It is a plaindrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81447239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9153 + ... + 15705.

Almost surely, 2^81447237 is an apocalyptic number.

It is an amenable number.

81447237 is a deficient number, since it is larger than the sum of its proper divisors (36301927).

81447237 is a wasteful number, since it uses less digits than its factorization.

81447237 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7940 (or 7937 counting only the distinct ones).

The product of its digits is 37632, while the sum is 36.

The square root of 81447237 is about 9024.8122972170. The cubic root of 81447237 is about 433.4697400285.

The spelling of 81447237 in words is "eighty-one million, four hundred forty-seven thousand, two hundred thirty-seven".