77721663 has 8 divisors (see below), whose sum is σ = 104315776. Its totient is φ = 51471000.

The previous prime is 77721661. The next prime is 77721673. The reversal of 77721663 is 36612777.

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

It is not a de Polignac number, because 77721663 - 2¹ = 77721661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77721661) 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, 85333 + ... + 86238.

It is an arithmetic number, because the mean of its divisors is an integer number (13039472).

Almost surely, 2^77721663 is an apocalyptic number.

77721663 is a deficient number, since it is larger than the sum of its proper divisors (26594113).

77721663 is a wasteful number, since it uses less digits than its factorization.

77721663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171725.

The product of its digits is 74088, while the sum is 39.

The square root of 77721663 is about 8815.9890539859. The cubic root of 77721663 is about 426.7570406571.

The spelling of 77721663 in words is "seventy-seven million, seven hundred twenty-one thousand, six hundred sixty-three".