77840021425 has 12 divisors (see below), whose sum is σ = 98103950236. Its totient is φ = 61251163200.

The previous prime is 77840021407. The next prime is 77840021437. The reversal of 77840021425 is 52412004877.

It can be written as a sum of positive squares in 6 ways, for example, as 29112549376 + 48727472049 = 170624^2 + 220743^2 .

It is not a de Polignac number, because 77840021425 - 2⁷ = 77840021297 is a prime.

It is a hoax number, since the sum of its digits (40) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 25519794 + ... + 25522843.

Almost surely, 2^77840021425 is an apocalyptic number.

It is an amenable number.

77840021425 is a deficient number, since it is larger than the sum of its proper divisors (20263928811).

77840021425 is a wasteful number, since it uses less digits than its factorization.

77840021425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51042708 (or 51042703 counting only the distinct ones).

The product of its (nonzero) digits is 125440, while the sum is 40.

The spelling of 77840021425 in words is "seventy-seven billion, eight hundred forty million, twenty-one thousand, four hundred twenty-five".