81023040 has 168 divisors, whose sum is σ = 318576960. Its totient is φ = 18514944.

The previous prime is 81023039. The next prime is 81023053. The reversal of 81023040 is 4032018.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (168).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18151 + ... + 22169.

Almost surely, 2^81023040 is an apocalyptic number.

81023040 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81023040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (159288480).

81023040 is an abundant number, since it is smaller than the sum of its proper divisors (237553920).

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

81023040 is a wasteful number, since it uses less digits than its factorization.

81023040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4049 (or 4036 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 81023040 is about 9001.2799089907. The cubic root of 81023040 is about 432.7158911909.

Adding to 81023040 its reverse (4032018), we get a palindrome (85055058).

It can be divided in two parts, 810 and 23040, that multiplied together give a square (18662400 = 4320²).

The spelling of 81023040 in words is "eighty-one million, twenty-three thousand, forty".