77912869 has 4 divisors (see below), whose sum is σ = 77990796. Its totient is φ = 77834944.

The previous prime is 77912867. The next prime is 77912897. The reversal of 77912869 is 96821977.

It is a happy number.

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 16916769 + 60996100 = 4113^2 + 7810^2 .

It is a cyclic number.

It is not a de Polignac number, because 77912869 - 2¹ = 77912867 is a prime.

It is a super-2 number, since 2×77912869² = 12140830311622322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77912867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 37444 + ... + 39469.

It is an arithmetic number, because the mean of its divisors is an integer number (19497699).

Almost surely, 2^77912869 is an apocalyptic number.

It is an amenable number.

77912869 is a deficient number, since it is larger than the sum of its proper divisors (77927).

77912869 is a wasteful number, since it uses less digits than its factorization.

77912869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77926.

The product of its digits is 381024, while the sum is 49.

The square root of 77912869 is about 8826.8266664753. The cubic root of 77912869 is about 427.1067144389.

The spelling of 77912869 in words is "seventy-seven million, nine hundred twelve thousand, eight hundred sixty-nine".