77545621 has 2 divisors, whose sum is σ = 77545622. Its totient is φ = 77545620.

The previous prime is 77545607. The next prime is 77545639. The reversal of 77545621 is 12654577.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 75881521 + 1664100 = 8711^2 + 1290^2 .

It is a cyclic number.

It is not a de Polignac number, because 77545621 - 2²¹ = 75448469 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77545651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38772810 + 38772811.

It is an arithmetic number, because the mean of its divisors is an integer number (38772811).

Almost surely, 2^77545621 is an apocalyptic number.

It is an amenable number.

77545621 is a deficient number, since it is larger than the sum of its proper divisors (1).

77545621 is an equidigital number, since it uses as much as digits as its factorization.

77545621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 58800, while the sum is 37.

The square root of 77545621 is about 8805.9991483079. Note that the first 3 decimals coincide. The cubic root of 77545621 is about 426.4345910622.

The spelling of 77545621 in words is "seventy-seven million, five hundred forty-five thousand, six hundred twenty-one".