77506621 has 6 divisors (see below), whose sum is σ = 82334330. Its totient is φ = 72947136.

The previous prime is 77506609. The next prime is 77506631. The reversal of 77506621 is 12660577.

It can be written as a sum of positive squares in 3 ways, for example, as 56475225 + 21031396 = 7515^2 + 4586^2 .

It is not a de Polignac number, because 77506621 - 2⁷ = 77506493 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 (77506631) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 133806 + ... + 134383.

Almost surely, 2^77506621 is an apocalyptic number.

It is an amenable number.

77506621 is a deficient number, since it is larger than the sum of its proper divisors (4827709).

77506621 is a wasteful number, since it uses less digits than its factorization.

77506621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 268223 (or 268206 counting only the distinct ones).

The product of its (nonzero) digits is 17640, while the sum is 34.

The square root of 77506621 is about 8803.7844703287. The cubic root of 77506621 is about 426.3630901931.

The spelling of 77506621 in words is "seventy-seven million, five hundred six thousand, six hundred twenty-one".