77725621 has 4 divisors (see below), whose sum is σ = 77746144. Its totient is φ = 77705100.

The previous prime is 77725607. The next prime is 77725657. The reversal of 77725621 is 12652777.

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.

It is a cyclic number.

It is not a de Polignac number, because 77725621 - 2¹⁷ = 77594549 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 (77725691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2745 + ... + 12766.

It is an arithmetic number, because the mean of its divisors is an integer number (19436536).

Almost surely, 2^77725621 is an apocalyptic number.

It is an amenable number.

77725621 is a deficient number, since it is larger than the sum of its proper divisors (20523).

77725621 is a wasteful number, since it uses less digits than its factorization.

77725621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20522.

The product of its digits is 41160, while the sum is 37.

The square root of 77725621 is about 8816.2135296282. The cubic root of 77725621 is about 426.7642847794.

The spelling of 77725621 in words is "seventy-seven million, seven hundred twenty-five thousand, six hundred twenty-one".