77431985 has 8 divisors (see below), whose sum is σ = 95184936. Its totient is φ = 60434560.

The previous prime is 77431979. The next prime is 77432023. The reversal of 77431985 is 58913477.

It can be written as a sum of positive squares in 4 ways, for example, as 1236544 + 76195441 = 1112^2 + 8729^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 77431985 - 2¹⁶ = 77366449 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 188654 + ... + 189063.

It is an arithmetic number, because the mean of its divisors is an integer number (11898117).

Almost surely, 2^77431985 is an apocalyptic number.

It is an amenable number.

77431985 is a deficient number, since it is larger than the sum of its proper divisors (17752951).

77431985 is a wasteful number, since it uses less digits than its factorization.

77431985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 377763.

The product of its digits is 211680, while the sum is 44.

The square root of 77431985 is about 8799.5445904888. The cubic root of 77431985 is about 426.2261889618.

The spelling of 77431985 in words is "seventy-seven million, four hundred thirty-one thousand, nine hundred eighty-five".