81399950 has 24 divisors (see below), whose sum is σ = 151645800. Its totient is φ = 32508000.

The previous prime is 81399943. The next prime is 81399959. The reversal of 81399950 is 5999318.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81399959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 51776 + ... + 53324.

It is an arithmetic number, because the mean of its divisors is an integer number (6318575).

Almost surely, 2^81399950 is an apocalyptic number.

81399950 is a deficient number, since it is larger than the sum of its proper divisors (70245850).

81399950 is a wasteful number, since it uses less digits than its factorization.

81399950 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2612 (or 2607 counting only the distinct ones).

The product of its (nonzero) digits is 87480, while the sum is 44.

The square root of 81399950 is about 9022.1920839672. The cubic root of 81399950 is about 433.3858351903.

The spelling of 81399950 in words is "eighty-one million, three hundred ninety-nine thousand, nine hundred fifty".