81225078 has 32 divisors (see below), whose sum is σ = 178803072. Its totient is φ = 24393600.

The previous prime is 81225077. The next prime is 81225113. The reversal of 81225078 is 87052218.

It is a super-2 number, since 2×81225078² = 13195026592212168, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81225077) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2013 + ... + 12903.

It is an arithmetic number, because the mean of its divisors is an integer number (5587596).

Almost surely, 2^81225078 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81225078, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (89401536).

81225078 is an abundant number, since it is smaller than the sum of its proper divisors (97577994).

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

81225078 is a wasteful number, since it uses less digits than its factorization.

81225078 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11020.

The product of its (nonzero) digits is 8960, while the sum is 33.

The square root of 81225078 is about 9012.4956588062. The cubic root of 81225078 is about 433.0752642219.

The spelling of 81225078 in words is "eighty-one million, two hundred twenty-five thousand, seventy-eight".