81152623778 has 4 divisors (see below), whose sum is σ = 121728935670. Its totient is φ = 40576311888.

The previous prime is 81152623723. The next prime is 81152623789. The reversal of 81152623778 is 87732625118.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 53394731329 + 27757892449 = 231073^2 + 166607^2 .

It is a super-3 number, since 3×81152623778³ (a number of 34 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20288155943 + ... + 20288155946.

Almost surely, 2^81152623778 is an apocalyptic number.

81152623778 is a deficient number, since it is larger than the sum of its proper divisors (40576311892).

81152623778 is a wasteful number, since it uses less digits than its factorization.

81152623778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40576311891.

The product of its digits is 1128960, while the sum is 50.

The spelling of 81152623778 in words is "eighty-one billion, one hundred fifty-two million, six hundred twenty-three thousand, seven hundred seventy-eight".