81247732 has 12 divisors (see below), whose sum is σ = 145651716. Its totient is φ = 39632960.

The previous prime is 81247721. The next prime is 81247757. The reversal of 81247732 is 23774218.

It can be written as a sum of positive squares in 2 ways, for example, as 38266596 + 42981136 = 6186^2 + 6556^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 247543 + ... + 247870.

It is an arithmetic number, because the mean of its divisors is an integer number (12137643).

Almost surely, 2^81247732 is an apocalyptic number.

81247732 is a gapful number since it is divisible by the number (82) formed by its first and last digit.

It is an amenable number.

81247732 is a deficient number, since it is larger than the sum of its proper divisors (64403984).

81247732 is a wasteful number, since it uses less digits than its factorization.

81247732 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 495458 (or 495456 counting only the distinct ones).

The product of its digits is 18816, while the sum is 34.

The square root of 81247732 is about 9013.7523817775. The cubic root of 81247732 is about 433.1155226221.

The spelling of 81247732 in words is "eighty-one million, two hundred forty-seven thousand, seven hundred thirty-two".