81261802 has 8 divisors (see below), whose sum is σ = 129062916. Its totient is φ = 38240832.

The previous prime is 81261793. The next prime is 81261823. The reversal of 81261802 is 20816218.

It can be written as a sum of positive squares in 2 ways, for example, as 73977201 + 7284601 = 8601^2 + 2699^2 .

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

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, 1194993 + ... + 1195060.

Almost surely, 2^81261802 is an apocalyptic number.

81261802 is a deficient number, since it is larger than the sum of its proper divisors (47801114).

81261802 is a wasteful number, since it uses less digits than its factorization.

81261802 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2390072.

The product of its (nonzero) digits is 1536, while the sum is 28.

The square root of 81261802 is about 9014.5328220602. The cubic root of 81261802 is about 433.1405226376.

The spelling of 81261802 in words is "eighty-one million, two hundred sixty-one thousand, eight hundred two".