77813281 has 16 divisors (see below), whose sum is σ = 96538624. Its totient is φ = 61072704.

The previous prime is 77813279. The next prime is 77813287. The reversal of 77813281 is 18231877.

It is not a de Polignac number, because 77813281 - 2¹ = 77813279 is a prime.

It is a super-2 number, since 2×77813281² = 12109813399969922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 77813281.

It is not an unprimeable number, because it can be changed into a prime (77813287) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8191 + ... + 14923.

It is an arithmetic number, because the mean of its divisors is an integer number (6033664).

Almost surely, 2^77813281 is an apocalyptic number.

It is an amenable number.

77813281 is a deficient number, since it is larger than the sum of its proper divisors (18725343).

77813281 is a wasteful number, since it uses less digits than its factorization.

77813281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6880.

The product of its digits is 18816, while the sum is 37.

The square root of 77813281 is about 8821.1836507353. The cubic root of 77813281 is about 426.9246613349.

The spelling of 77813281 in words is "seventy-seven million, eight hundred thirteen thousand, two hundred eighty-one".