81440250 has 32 divisors (see below), whose sum is σ = 203276736. Its totient is φ = 21717200.

The previous prime is 81440173. The next prime is 81440273. The reversal of 81440250 is 5204418.

It is a self number, because there is not a number n which added to its sum of digits gives 81440250.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 53544 + ... + 55043.

It is an arithmetic number, because the mean of its divisors is an integer number (6352398).

Almost surely, 2^81440250 is an apocalyptic number.

81440250 is an abundant number, since it is smaller than the sum of its proper divisors (121836486).

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

81440250 is a wasteful number, since it uses less digits than its factorization.

81440250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108607 (or 108597 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 24.

The square root of 81440250 is about 9024.4251894511. The cubic root of 81440250 is about 433.4573445203.

Adding to 81440250 its reverse (5204418), we get a palindrome (86644668).

The spelling of 81440250 in words is "eighty-one million, four hundred forty thousand, two hundred fifty".