81963646 has 16 divisors (see below), whose sum is σ = 125907984. Its totient is φ = 40005504.

The previous prime is 81963631. The next prime is 81963653. The reversal of 81963646 is 64636918.

It is a super-2 number, since 2×81963646² = 13436078531226632, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12436 + ... + 17848.

It is an arithmetic number, because the mean of its divisors is an integer number (7869249).

Almost surely, 2^81963646 is an apocalyptic number.

81963646 is a deficient number, since it is larger than the sum of its proper divisors (43944338).

81963646 is a wasteful number, since it uses less digits than its factorization.

81963646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5595.

The product of its digits is 186624, while the sum is 43.

The square root of 81963646 is about 9053.3776017573. The cubic root of 81963646 is about 434.3839361273.

The spelling of 81963646 in words is "eighty-one million, nine hundred sixty-three thousand, six hundred forty-six".