77672821 has 4 divisors (see below), whose sum is σ = 77698144. Its totient is φ = 77647500.

The previous prime is 77672807. The next prime is 77672857. The reversal of 77672821 is 12827677.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12827677 = 179 ⋅71663.

It is a cyclic number.

It is not a de Polignac number, because 77672821 - 2⁵ = 77672789 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 (77672321) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7305 + ... + 14446.

It is an arithmetic number, because the mean of its divisors is an integer number (19424536).

Almost surely, 2^77672821 is an apocalyptic number.

It is an amenable number.

77672821 is a deficient number, since it is larger than the sum of its proper divisors (25323).

77672821 is a wasteful number, since it uses less digits than its factorization.

77672821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25322.

The product of its digits is 65856, while the sum is 40.

The square root of 77672821 is about 8813.2185380824. The cubic root of 77672821 is about 426.6676274257.

The spelling of 77672821 in words is "seventy-seven million, six hundred seventy-two thousand, eight hundred twenty-one".