77308821 has 48 divisors (see below), whose sum is σ = 120294720. Its totient is φ = 47773440.

The previous prime is 77308807. The next prime is 77308859. The reversal of 77308821 is 12880377.

It is not a de Polignac number, because 77308821 - 2⁶ = 77308757 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77308921) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1153830 + ... + 1153896.

It is an arithmetic number, because the mean of its divisors is an integer number (2506140).

Almost surely, 2^77308821 is an apocalyptic number.

It is an amenable number.

77308821 is a deficient number, since it is larger than the sum of its proper divisors (42985899).

77308821 is a wasteful number, since it uses less digits than its factorization.

77308821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 226 (or 223 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 36.

The square root of 77308821 is about 8792.5434886613. The cubic root of 77308821 is about 426.0000826555. Note that the first 4 decimals are identical.

The spelling of 77308821 in words is "seventy-seven million, three hundred eight thousand, eight hundred twenty-one".