77661643 has 8 divisors (see below), whose sum is σ = 79450112. Its totient is φ = 75891816.

The previous prime is 77661629. The next prime is 77661653. The reversal of 77661643 is 34616677.

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

It is a cyclic number.

It is not a de Polignac number, because 77661643 - 2⁵ = 77661611 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 77661596 and 77661605.

It is not an unprimeable number, because it can be changed into a prime (77661653) 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 7 ways as a sum of consecutive naturals, for example, 3946 + ... + 13072.

It is an arithmetic number, because the mean of its divisors is an integer number (9931264).

Almost surely, 2^77661643 is an apocalyptic number.

77661643 is a deficient number, since it is larger than the sum of its proper divisors (1788469).

77661643 is a wasteful number, since it uses less digits than its factorization.

77661643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9321.

The product of its digits is 127008, while the sum is 40.

The square root of 77661643 is about 8812.5843542062. The cubic root of 77661643 is about 426.6471590066.

It can be divided in two parts, 7766 and 1643, that added together give a square (9409 = 97²).

The spelling of 77661643 in words is "seventy-seven million, six hundred sixty-one thousand, six hundred forty-three".