77923821 has 16 divisors (see below), whose sum is σ = 106928640. Its totient is φ = 50446080.

The previous prime is 77923763. The next prime is 77923831. The reversal of 77923821 is 12832977.

It is not a de Polignac number, because 77923821 - 2¹¹ = 77921773 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 77923821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77923831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27300 + ... + 30018.

It is an arithmetic number, because the mean of its divisors is an integer number (6683040).

Almost surely, 2^77923821 is an apocalyptic number.

It is an amenable number.

77923821 is a deficient number, since it is larger than the sum of its proper divisors (29004819).

77923821 is a wasteful number, since it uses less digits than its factorization.

77923821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2996.

The product of its digits is 42336, while the sum is 39.

The square root of 77923821 is about 8827.4470261792. The cubic root of 77923821 is about 427.1267259109.

The spelling of 77923821 in words is "seventy-seven million, nine hundred twenty-three thousand, eight hundred twenty-one".