81199855 has 16 divisors (see below), whose sum is σ = 109965600. Its totient is φ = 57016960.

The previous prime is 81199849. The next prime is 81199861. The reversal of 81199855 is 55899118.

It is an interprime number because it is at equal distance from previous prime (81199849) and next prime (81199861).

It is not a de Polignac number, because 81199855 - 2³ = 81199847 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23860 + ... + 27049.

It is an arithmetic number, because the mean of its divisors is an integer number (6872850).

Almost surely, 2^81199855 is an apocalyptic number.

81199855 is a deficient number, since it is larger than the sum of its proper divisors (28765745).

81199855 is a wasteful number, since it uses less digits than its factorization.

81199855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50954.

The product of its digits is 129600, while the sum is 46.

The square root of 81199855 is about 9011.0962152227. The cubic root of 81199855 is about 433.0304316466.

The spelling of 81199855 in words is "eighty-one million, one hundred ninety-nine thousand, eight hundred fifty-five".