81785402 has 16 divisors (see below), whose sum is σ = 130108032. Its totient is φ = 38424000.

The previous prime is 81785377. The next prime is 81785449. The reversal of 81785402 is 20458718.

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 7 ways as a sum of consecutive naturals, for example, 23933 + ... + 27135.

It is an arithmetic number, because the mean of its divisors is an integer number (8131752).

Almost surely, 2^81785402 is an apocalyptic number.

81785402 is a deficient number, since it is larger than the sum of its proper divisors (48322630).

81785402 is a wasteful number, since it uses less digits than its factorization.

81785402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3973.

The product of its (nonzero) digits is 17920, while the sum is 35.

The square root of 81785402 is about 9043.5281831816. The cubic root of 81785402 is about 434.0688268172.

The spelling of 81785402 in words is "eighty-one million, seven hundred eighty-five thousand, four hundred two".