77115623809 has 9 divisors (see below), whose sum is σ = 89708191041. Its totient is φ = 66097439940.

The previous prime is 77115623803. The next prime is 77115623833. The reversal of 77115623809 is 90832651177.

It is a happy number.

The square root of 77115623809 is 277697.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 77115623809 - 2¹³ = 77115615617 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is not an unprimeable number, because it can be changed into a prime (77115623803) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1924044 + ... + 1963714.

Almost surely, 2^77115623809 is an apocalyptic number.

77115623809 is the 277697-th square number.

77115623809 is the 138849-th centered octagonal number.

It is an amenable number.

77115623809 is a deficient number, since it is larger than the sum of its proper divisors (12592567232).

77115623809 is an frugal number, since it uses more digits than its factorization.

77115623809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79356 (or 39678 counting only the distinct ones).

The product of its (nonzero) digits is 635040, while the sum is 49.

Multiplying 77115623809 by its sum of digits (49), we get a square (3778665566641 = 1943879²).

77115623809 divided by its sum of digits (49) gives a square (1573788241 = 39671²).

The spelling of 77115623809 in words is "seventy-seven billion, one hundred fifteen million, six hundred twenty-three thousand, eight hundred nine".