77020561 has 4 divisors (see below), whose sum is σ = 77127232. Its totient is φ = 76913892.

The previous prime is 77020529. The next prime is 77020571. The reversal of 77020561 is 16502077.

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, and also an emirpimes, since its reverse is a distinct semiprime: 16502077 = 1567 ⋅10531.

It is a cyclic number.

It is not a de Polignac number, because 77020561 - 2⁵ = 77020529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77020571) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 52245 + ... + 53698.

It is an arithmetic number, because the mean of its divisors is an integer number (19281808).

Almost surely, 2^77020561 is an apocalyptic number.

It is an amenable number.

77020561 is a deficient number, since it is larger than the sum of its proper divisors (106671).

77020561 is a wasteful number, since it uses less digits than its factorization.

77020561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106670.

The product of its (nonzero) digits is 2940, while the sum is 28.

The square root of 77020561 is about 8776.1358808988. The cubic root of 77020561 is about 425.4699502806.

The spelling of 77020561 in words is "seventy-seven million, twenty thousand, five hundred sixty-one".