81029855 has 4 divisors (see below), whose sum is σ = 97235832. Its totient is φ = 64823880.

The previous prime is 81029849. The next prime is 81029869. The reversal of 81029855 is 55892018.

It is a semiprime because it is the product of two primes.

It is a de Polignac number, because none of the positive numbers 2^k-81029855 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8102981 + ... + 8102990.

It is an arithmetic number, because the mean of its divisors is an integer number (24308958).

Almost surely, 2^81029855 is an apocalyptic number.

81029855 is a deficient number, since it is larger than the sum of its proper divisors (16205977).

81029855 is a wasteful number, since it uses less digits than its factorization.

81029855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16205976.

The product of its (nonzero) digits is 28800, while the sum is 38.

The square root of 81029855 is about 9001.6584583064. The cubic root of 81029855 is about 432.7280230328.

The spelling of 81029855 in words is "eighty-one million, twenty-nine thousand, eight hundred fifty-five".