77891661897345 has 24 divisors (see below), whose sum is σ = 135012699634176. Its totient is φ = 41542070239008.

The previous prime is 77891661897331. The next prime is 77891661897389. The reversal of 77891661897345 is 54379816619877.

77891661897345 is a `hidden beast` number, since 7 + 7 + 8 + 91 + 6 + 6 + 189 + 7 + 345 = 666.

It is not a de Polignac number, because 77891661897345 - 2⁹ = 77891661896833 is a prime.

It is a super-2 number, since 2×77891661897345² (a number of 29 digits) contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10156614 + ... + 16091616.

It is an arithmetic number, because the mean of its divisors is an integer number (5625529151424).

Almost surely, 2^{77891661897345} is an apocalyptic number.

It is an amenable number.

77891661897345 is a deficient number, since it is larger than the sum of its proper divisors (57121037736831).

77891661897345 is a wasteful number, since it uses less digits than its factorization.

77891661897345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6226661 (or 6226658 counting only the distinct ones).

The product of its digits is 3840721920, while the sum is 81.

The spelling of 77891661897345 in words is "seventy-seven trillion, eight hundred ninety-one billion, six hundred sixty-one million, eight hundred ninety-seven thousand, three hundred forty-five".