81651902 has 8 divisors (see below), whose sum is σ = 122743776. Its totient is φ = 40737312.

The previous prime is 81651841. The next prime is 81651943. The reversal of 81651902 is 20915618.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 43163 + ... + 45014.

It is an arithmetic number, because the mean of its divisors is an integer number (15342972).

Almost surely, 2^81651902 is an apocalyptic number.

81651902 is a deficient number, since it is larger than the sum of its proper divisors (41091874).

81651902 is a wasteful number, since it uses less digits than its factorization.

81651902 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88642.

The product of its (nonzero) digits is 4320, while the sum is 32.

The square root of 81651902 is about 9036.1441998233. The cubic root of 81651902 is about 433.8325183579.

The spelling of 81651902 in words is "eighty-one million, six hundred fifty-one thousand, nine hundred two".