81153904 has 40 divisors (see below), whose sum is σ = 171051552. Its totient is φ = 37075200.

The previous prime is 81153901. The next prime is 81153949. The reversal of 81153904 is 40935118.

It is a super-2 number, since 2×81153904² = 13171912268882432, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81153901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19077 + ... + 22939.

Almost surely, 2^81153904 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 81153904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85525776).

81153904 is an abundant number, since it is smaller than the sum of its proper divisors (89897648).

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

81153904 is a wasteful number, since it uses less digits than its factorization.

81153904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3985 (or 3979 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 81153904 is about 9008.5461646150. The cubic root of 81153904 is about 432.9487322561.

The spelling of 81153904 in words is "eighty-one million, one hundred fifty-three thousand, nine hundred four".