77447991 has 8 divisors (see below), whose sum is σ = 104229504. Its totient is φ = 51149240.

The previous prime is 77447927. The next prime is 77448071. The reversal of 77447991 is 19974477.

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 77447991 - 2⁶ = 77447927 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 77447991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77447921) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 120315 + ... + 120956.

It is an arithmetic number, because the mean of its divisors is an integer number (13028688).

Almost surely, 2^77447991 is an apocalyptic number.

77447991 is a deficient number, since it is larger than the sum of its proper divisors (26781513).

77447991 is a wasteful number, since it uses less digits than its factorization.

77447991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241381.

The product of its digits is 444528, while the sum is 48.

The square root of 77447991 is about 8800.4540223786. The cubic root of 77447991 is about 426.2555554067.

The spelling of 77447991 in words is "seventy-seven million, four hundred forty-seven thousand, nine hundred ninety-one".