81162550 has 24 divisors (see below), whose sum is σ = 172529136. Its totient is φ = 27827040.

The previous prime is 81162541. The next prime is 81162553. The reversal of 81162550 is 5526118.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81162553) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 115597 + ... + 116296.

It is an arithmetic number, because the mean of its divisors is an integer number (7188714).

Almost surely, 2^81162550 is an apocalyptic number.

81162550 is an abundant number, since it is smaller than the sum of its proper divisors (91366586).

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

81162550 is a wasteful number, since it uses less digits than its factorization.

81162550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 231912 (or 231907 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 28.

The square root of 81162550 is about 9009.0260294884. The cubic root of 81162550 is about 432.9641069192.

Adding to 81162550 its reverse (5526118), we get a palindrome (86688668).

The spelling of 81162550 in words is "eighty-one million, one hundred sixty-two thousand, five hundred fifty".