77849721 has 8 divisors (see below), whose sum is σ = 115332960. Its totient is φ = 51899796.

The previous prime is 77849699. The next prime is 77849741. The reversal of 77849721 is 12794877.

It is a happy number.

It is not a de Polignac number, because 77849721 - 2⁶ = 77849657 is a prime.

It is not an unprimeable number, because it can be changed into a prime (77849741) 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, 1441635 + ... + 1441688.

It is an arithmetic number, because the mean of its divisors is an integer number (14416620).

Almost surely, 2^77849721 is an apocalyptic number.

It is an amenable number.

77849721 is a deficient number, since it is larger than the sum of its proper divisors (37483239).

77849721 is a wasteful number, since it uses less digits than its factorization.

77849721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2883332 (or 2883326 counting only the distinct ones).

The product of its digits is 197568, while the sum is 45.

The square root of 77849721 is about 8823.2488914232. The cubic root of 77849721 is about 426.9912939483.

The spelling of 77849721 in words is "seventy-seven million, eight hundred forty-nine thousand, seven hundred twenty-one".