7815133985 has 4 divisors (see below), whose sum is σ = 9378160788. Its totient is φ = 6252107184.

The previous prime is 7815133951. The next prime is 7815133999. The reversal of 7815133985 is 5893315187.

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

It can be written as a sum of positive squares in 2 ways, for example, as 4368152464 + 3446981521 = 66092^2 + 58711^2 .

It is a cyclic number.

It is not a de Polignac number, because 7815133985 - 2¹⁰ = 7815132961 is a prime.

It is a super-2 number, since 2×7815133985² (a number of 21 digits) contains 22 as substring.

It is a Duffinian 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, 781513394 + ... + 781513403.

It is an arithmetic number, because the mean of its divisors is an integer number (2344540197).

Almost surely, 2^7815133985 is an apocalyptic number.

It is an amenable number.

7815133985 is a deficient number, since it is larger than the sum of its proper divisors (1563026803).

7815133985 is a wasteful number, since it uses less digits than its factorization.

7815133985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1563026802.

The product of its digits is 907200, while the sum is 50.

The square root of 7815133985 is about 88403.2464618806. The cubic root of 7815133985 is about 1984.4742867337.

The spelling of 7815133985 in words is "seven billion, eight hundred fifteen million, one hundred thirty-three thousand, nine hundred eighty-five".