81078372 has 54 divisors (see below), whose sum is σ = 217740978. Its totient is φ = 25433088.

The previous prime is 81078343. The next prime is 81078383. The reversal of 81078372 is 27387018.

It can be written as a sum of positive squares in 3 ways, for example, as 57517056 + 23561316 = 7584^2 + 4854^2 .

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 pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 6508 + ... + 14300.

Almost surely, 2^81078372 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81078372, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108870489).

81078372 is an abundant number, since it is smaller than the sum of its proper divisors (136662606).

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

81078372 is a wasteful number, since it uses less digits than its factorization.

81078372 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7837 (or 7815 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 36.

The square root of 81078372 is about 9004.3529473250. The cubic root of 81078372 is about 432.8143717688.

The spelling of 81078372 in words is "eighty-one million, seventy-eight thousand, three hundred seventy-two".