81538254 has 72 divisors (see below), whose sum is σ = 207005760. Its totient is φ = 23127552.

The previous prime is 81538211. The next prime is 81538267. The reversal of 81538254 is 45283518.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 169987 + ... + 170465.

It is an arithmetic number, because the mean of its divisors is an integer number (2875080).

Almost surely, 2^81538254 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81538254, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (103502880).

81538254 is an abundant number, since it is smaller than the sum of its proper divisors (125467506).

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

81538254 is a wasteful number, since it uses less digits than its factorization.

81538254 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 694 (or 684 counting only the distinct ones).

The product of its digits is 38400, while the sum is 36.

The square root of 81538254 is about 9029.8534871835. The cubic root of 81538254 is about 433.6311468879.

The spelling of 81538254 in words is "eighty-one million, five hundred thirty-eight thousand, two hundred fifty-four".