77517200021 has 4 divisors (see below), whose sum is σ = 77527403232. Its totient is φ = 77506996812.

The previous prime is 77517199999. The next prime is 77517200023. The reversal of 77517200021 is 12000271577.

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 77517200021 - 2¹⁴ = 77517183637 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77517200023) 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, 5090201 + ... + 5105406.

It is an arithmetic number, because the mean of its divisors is an integer number (19381850808).

Almost surely, 2^77517200021 is an apocalyptic number.

It is an amenable number.

77517200021 is a deficient number, since it is larger than the sum of its proper divisors (10203211).

77517200021 is a wasteful number, since it uses less digits than its factorization.

77517200021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10203210.

The product of its (nonzero) digits is 6860, while the sum is 32.

Adding to 77517200021 its reverse (12000271577), we get a palindrome (89517471598).

The spelling of 77517200021 in words is "seventy-seven billion, five hundred seventeen million, two hundred thousand, twenty-one".