81855402 has 16 divisors (see below), whose sum is σ = 167518560. Its totient is φ = 26650512.

The previous prime is 81855377. The next prime is 81855419. The reversal of 81855402 is 20455818.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 158377 + ... + 158892.

It is an arithmetic number, because the mean of its divisors is an integer number (10469910).

Almost surely, 2^81855402 is an apocalyptic number.

81855402 is an abundant number, since it is smaller than the sum of its proper divisors (85663158).

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

81855402 is a wasteful number, since it uses less digits than its factorization.

81855402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 317317.

The product of its (nonzero) digits is 12800, while the sum is 33.

The square root of 81855402 is about 9047.3975263608. The cubic root of 81855402 is about 434.1926311167.

The spelling of 81855402 in words is "eighty-one million, eight hundred fifty-five thousand, four hundred two".