77867621 has 4 divisors (see below), whose sum is σ = 83857452. Its totient is φ = 71877792.

The previous prime is 77867611. The next prime is 77867641. The reversal of 77867621 is 12676877.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12676877 = 3499 ⋅3623.

It can be written as a sum of positive squares in 2 ways, for example, as 38316100 + 39551521 = 6190^2 + 6289^2 .

It is a cyclic number.

It is not a de Polignac number, because 77867621 - 2¹⁰ = 77866597 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 (77867611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2994896 + ... + 2994921.

It is an arithmetic number, because the mean of its divisors is an integer number (20964363).

Almost surely, 2^77867621 is an apocalyptic number.

It is an amenable number.

77867621 is a deficient number, since it is larger than the sum of its proper divisors (5989831).

77867621 is a wasteful number, since it uses less digits than its factorization.

77867621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5989830.

The product of its digits is 197568, while the sum is 44.

The square root of 77867621 is about 8824.2631987039. The cubic root of 77867621 is about 427.0240175014.

The spelling of 77867621 in words is "seventy-seven million, eight hundred sixty-seven thousand, six hundred twenty-one".