81252217642690 has 16 divisors (see below), whose sum is σ = 153951570270720. Its totient is φ = 30790314054000.

The previous prime is 81252217642567. The next prime is 81252217642727. The reversal of 81252217642690 is 9624671225218.

It is a super-2 number, since 2×81252217642690² (a number of 29 digits) contains 22 as substring.

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, 213821625186 + ... + 213821625565.

It is an arithmetic number, because the mean of its divisors is an integer number (9621973141920).

Almost surely, 2^{81252217642690} is an apocalyptic number.

81252217642690 is a deficient number, since it is larger than the sum of its proper divisors (72699352628030).

81252217642690 is a wasteful number, since it uses less digits than its factorization.

81252217642690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 427643250777.

The product of its (nonzero) digits is 5806080, while the sum is 55.

The spelling of 81252217642690 in words is "eighty-one trillion, two hundred fifty-two billion, two hundred seventeen million, six hundred forty-two thousand, six hundred ninety".